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College  of  pbitfictans  anb  gmrgeona 


Reference  JLibxaxy 


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1 

* 


PEELIMINAEY  COUESE  LECTUEES 

ON 
PHYSIOLOGY. 


Entered  according1  to  Act  of  Congress,  in  the  year  1875, 
In  the  office  of  the  Librarian  of  Congress,  at  Washington,  D.  C. 


PHYSIOLOGY: 


PRELIMINARY  COUESE  LECTURES, 


BY 

JAMES  T.  WHITTAKER,  M.A.,  M.D., 

PROFESSOR  OF  PHYSIOLOGY  AND  CLINICAL  MEDICINE  IN  THE  MEDICAL 

COLLEGE  OF   OHIO;    LECTURER  ON   CLINICAL  MEDICINE  AT  THE 

GOOD  SAMARITAN  HOSPITAL;  MEMBER  OF  THE  CINCINNATI 

ACADEMY   OF  MEDICINE,    AND  OF  THE   CINCINNATI 

JCIETY  OF  NATURAL  HISTORY: 


SOCI 


ON  THE  INFLUENCE  OF  PHYSIOLOGY  UPON  PRACTICE;  ON 
THE  CONSERVATION  OF  FORCE;  ON  THE  ORIGIN  OF  LIFE, 
AND  THE  EVOLUTION  OF  ITS  FORMS  ;    AND  ON  PRO- 
TOPLASM, BONE,  MUSCLE,  NERVE  AND  BLOOD. 


ILLUSTRATED. 


CINCINNATI: 

CHANCY  R.  MURRY,  103  W.  Sixth  St. 
1879. 


Die  Natur  weisz  allein  was  sie  will. 

Goethe;  Sprueche. 


To  make  man  mild  and  sociable  to  man 
^o  cultivate  the  wild  licentious  savage 
"With  wisdom,  discipline  and  liberal  arts 
Th'  embellishments  of  life. 

Addison;  Cato. 


I  DEDICATE 


\iz  Jpl?  mt& 


fttt&mfe 


AT  THE 


MEDICAL  COLLEGE  OF  OHIO. 


J.  T.  W. 


PEEFACE. 


I  have  endeavored  in  the  delivery  of  these  lectures 
to  put  within  the  reach  and  comprehension  of  the 
first  course  student  the  foundation  facts  and  princi- 
ples upon  which  the  stately  edifice  of  physiology  is 
built.  And  in  the  publication  of  them,  which  I  have 
only  presumed  to  venture  in  consequence  of  repeated 
requests  on  the  part  of  the  students  of  my  class,  I 
have  adhered  strictly  to  the  spirit,  and  as  far  as  I 
could,  to  the  letter  of  the  delivery.  This  explanation 
will  suffice,  I  hope,  to  excuse  the  latitude  of  expres- 
sion and  selection  which  would  be  accorded  to  off- 
hand, lecture-room,  delivery,  and  which  might  be 
inexcusable  in  a  text-book  compiled  for  the  more 
careful  study  of  leisure  hours. 

J.  T.  W. 

100  West  Eighth  St., 
Dec,  1878. 


CONTENTS. 


LECTURE     I. 

THE  INFLUENCE  OF  PHYSIOLOGY  UPON  PRACTICE  AND 
UPON  THE  PRACTITIONER. 

Dr.  Jacob  Primrose — The  Exercitatio  de  Motu  Cordis,  etc. — Science 
vs.  Practice — The  Fallacy  of  Experience — Some  Old  Receipts — Opin- 
ions of  Noted  Men — Sterne,  Shakespeare  and  Moliere — The  Royal 
Touch  and  the  Caul — Contributions  of  Physiology  to  Practice — The 
University  of  Naples — The  Modern  Physician — Gladstone's  Response 
— Harvey  and  Haller — Characteristics  of  Physiologists 1-23 

LECTURE     II. 

THE  CONSERVATION  OF  FORCE. 

The  Alphabet  of  Science— Indestructibility  of  Matter — No  Matter 
without  Force — Solar  Origin  of  Heat  of  Coal — Correlation  of  Forces — 
Machinery,  a  Means  of  Changing  Force — Clocks,  Water-Wheels, 
Winds,  Windmills  and  Steam  Engines — The  Equivalence  of  the 
Forces — The  Conservatory  of  Arts  and  Trades — Motion  from  Heat — 
Motion  from  Electricity — The  Electric  Light — The  Sun  as  the  Source 
of  Power — Source  of  Solar  Force — The  Nebular  Hypothesis — The 
Channel  of  Mt.  Pilatus — The  Perpetuity  of  Force — Physiological 
Force — Excretions,  the  Products  of  Combustion — Animal  Bodies  as 
Machines — The  Force  Value  of  Foods — Physiological,  Correlative 
with  Physical  Force 23-46 

LECTURE     III. 

THE  ORIGIN  AND  EVOLUTION  OF.LIFE. 

Definitions  of  Physiology — Ancient  Definitions  of  Life — Modern 
Definitions  of  Life — Difference  between  Organic  and  Inorganic  Matter 
— The  Property  of  Assimilation — Period  of  Development  of  Life— 
The  Theory  of  Evolution — Palaeontology — The  Cataclysms  of  Cuvier 
— The  Operation  of  Existing  Causes — The  Age  of  the  Earth — The 
Evolution  of  Fossil  Forms 47-63 


X  CONTENTS. 

LECTURE     IV. 

THE  EVOLUTION  OF  FORMS  OF  LIFE. 

Comparative  Anatomy — Of  the  Eye  and  the  Ear — Order  of  Develop- 
ment— Jean  Lamarck — Wilhelm  von  Goethe — The  Intermaxillary 
Process — Erasmus  Darwin — Anatomical  Resemblances — The  Hand 
and  its  Homologues — Comparative  Embryology — Ernst  Haeckel — 
The  Rudimentary  Organs — Bone  Rudiments — Muscle  Rudiments — 
Rudiments  from  the  Digestive  System — Other  Rudiments — Explana- 
tions of  Rudiments 64-83 

LECTURE     V. 

THE  EVOLUTION  OF  FORMS  OF  LIFE. 

The  Law  of  Inheritabiiity—  Transmission  of  Acquired  Defects — Ho- 
mochronous  Transmission — Atavism — The  Physics  of  Reproduction — 
Adaptation  to  External  Conditions — Difficulty  of  Classification — Arti- 
ficial Selection — The  Struggle  for  Existence — Natural  Selection — 
Protective  Colors — Warning  Colors — Sexual  Selection — Complications 
in  Natural  Selection — Preservation  of  the  Individual  and  of  the  Race 
—General  Summary „ 84-104 

LECTURE     VI. 

PROTOPLASM  AND  ITS  PROPERTIES. 

The  History  of  Histology — The  Invention  and  Use  of  the  Microscope 
— The  Discovery  and  Doctrine  of  The  Cell — Derivation  and  Im- 
port of  The  Cell— The  Cell  Wall— The  Nucleus  and  Nucleolus— The 
Cell  Contents  or  Protoplasm — The  Amoeba — The  Properties  of  Proto-  ■ 
plasm — Motion — The  Color  Changes  of  the  Chameleon — Ciliary  Mo- 
tion— Motion  of  Other  Cells — Molecular  Motion — Molecular  Changes 
in  the  Ovum — Parthenogenesis — Motion  as  the  Essence  of  Repro- 
duction   105-128 

LECTURE     VII. 

PROTOPLASM  AND  ITS  PROPERTIES. 

The  Chemistry  of  Organic  Matter — The  Ultimate  Elements — The 
Proximate  Principles — Albumen  and  its  Products — The  Chemistry 
of  the  Cell — Absorption  and  Assimilation — Metabolism — Oxidation 
Processes — Oxidation  in  the  Ovum — Oxidation  in  Muscle — Oxidation 
in  the  Blood — Oxidation  in  Nerve  Tissue — The  Quantity  of  Oxygen 
in  the  Body — The  Genesis  of  Protoplasm — Spontaneous  Generation — 
Omne  Vivum  ex  Ovo — Reproduction  and  Nutrition — Modes  of  Cell 
Genesis — Death  of  Cells — Recapitulation — Classifications  of  the 
Tissues 128-149 


CONTENTS.  XI 

LECTURE    VIII. 

BONE  AND  ITS  PROPERTIES. 

Anatomical  Dignity  of  Bone — Relation  of  Bone  to  Nerve  Tissue — 
The  Skeleton — The  General  Properties  of  Bones — The  Histology  of 
Bone — The  Haversian  Canals — The  Lamellae — The  Bone  Corpuscles 
and  Lacunae — The  Canaliculi — The  Chemistry  of  Bone— Difficulties 
Attending  the  Study  of  Osteology — Bones  as  Fuel — Gelatine  as  an 
Aliment — The  Resistance  and  Resilience  of  Bone — Constancy  of 
Chemical  Composition — Rachitis  and  Osteo-Malacia — The  Phosphate 
of  Lime — The  Preservation  of  Bone — Bone  a  Connective  Tissue — 
The  Formation  of  Bone — The  Periosteum — The  Centre  of  Ossification 
— The  Determination  of  Age — The  Femoral  Epiphyseal  Centre — The 
Excavation  of  Bone — Air  in  Bout: —  The  Marrow — Studies  in  Living 
Bone — Bone  as  a  Symbol  of  the  Body , 150-175 

LECTURE     IX. 

MUSCLE  AND  ITS  PROPERTIES. 

Etymology  of  Muscle — Muscular  Motion — Striped  and  Smooth  Mus- 
cle— The  Color  of  Muscle — The  Anatomy  of  Voluntary  Muscle — The 
Sarcolemma — The  Muscle  Fibre — Muscle  Protoplasm — General  Prop- 
erties of  Muscles — Names  of  Muscles — Form  and  Shape  of  Muscles — 
Smooth  Muscle — Disposition  of  Smooth  Muscle — The  Chemistry  of 
Muscle— The  Reaction  of  Muscle — Specific  Properties  of  Muscle — 
The  Elasticity  of  Muscle— The  Tonicity  of  Voluntary  Muscle—, 
Tonicity,  a  Reflex  Phenomenon— Tonicity  of  Involuntary  Mxiscle — 
The  Sensibility  of  Muscle— Sensibility  and  Sensation— The  Sensation 
of  Fatigue — The  Exercise  of  the  Muscular  Sense .....175-195 

LECTURE    X. 

MUSCLE  AND  ITS  PROPERTIES. 

Contractility  of  Muscle — Effects  of  Muscular  Contraction — Degree  of 
Contraction — Change  of  Form— Agents  which  Induce  Contraction — 
Direct  and  Indirect  Excitation— Thermal  Excitation— Electric  Excita- 
tion—The History  of  Galvanism — The  Action  of  Induced  Electricity 
— The  Action  of  Nerve  Force — The  Sound  of  Muscle  Contraction — 
The  Muscular  Wave — Independence  of  Muscular  Force — The  Action 
of  the  Sulphocyanide  of  Potassium  and  Curare— The  Generation  of 
Heat — The  Generation  of  Electricity — Du  Bois-Reymond's  Theory 
of  Muscular  Action— Rigor  Mortis— Post-Mortem  Changes  in  Muscle 
— The  Fuel  of  Muscle— The  Oxygen  Supply— The  Dependence  of 
Muscle  upon  Blood— The  Muscles  as  Levers — The  Absolute  Power 
■of  Muscle— The  Power  of  Muscle  in  General— Differences  of  the 
Sexes— Differences  in  Different  Animals— The  Velocity  and  Delicacy 
■of  Muscular  Action...^  , 195-222 


Xii  CONTENTS. 

LECTURE     XI. 

NERVE  AND  ITS  PROPERTIES. 

The  Prime  Function  of  Nervous  Tissue — Subordination  to  Other  Tis- 
sues— Independence  of  Nerve  Force — Genesis  of  Nerve  Force — Ar- 
rangement of  Nerve  Tissue — White  and  Gray  Matter — The  Cerebro- 
spinal and  Sympathetic  Systems — The  Nerve  Cells — The  Nerve  Fibres 
—The  Neurilemma— The  Axis  Cylinder— The  Gray  Fibres— The  Prop- 
erties of  Nerves — Terminations  of  Sensitive  Nerves — Terminations 
of  Motor  Nerves — Course  of  Nerve  Fibres — Identity  of  Nerve  Fibres 
— Indifference  of  Direction  of  Nerve  Force — The  Chemistry  of  Nerve 
Tissue — The  Action  of  Electricity  upon  Nerve  Tissue — The  Nature 
of  Nerve  Force — Rate  of  Conduction  of  Nerve  Force — Nerve  Force 
and  Electricity — Comparative  Velocity  of  Nerve  and  Other  Forms  of 
F'orce — The  Reception  and  Perception  of  Impressions — Ancient  Sig- 
nificance of  Nerves — The  Effects  of  Use  and  Disuse  and  of  Age 223-24S 

LECTURE     XII. 

THE  BLOOD  AND  ITS  PROPERTIES. 

The  Value  of  the  Blood— The  Transfusion  of  Blood— The  Constitu- 
tion of  the  Blood — The  Color  of  the  Blood — Reaction  of  the  Blood 
—The  Odor  of  the  Blood— The  Taste  of  the  Blood— The  Temperature 
of  the  Blood— The  Weight  of  the  Blood— The  Quantity  of  the  Blood 
— The  Morphology  of  the  Blood — The  Red  Blood  Corpuscles — Size 
of  the  Red  Corpuscles — Number  of  the  Red  Corpuscles — Elasticity 
of  the  Red  Corpuscle — Constitution  of  the  Red  Corpuscles — Use  of 
the  Red  Corpuscles — The  Colorless  Blood  Corpuscles — The  Blood 
Plasma — The  Coagulation  of  the  Blood — The  Blood  as  the  Substitute 
of  the  Body 247-272 

Index 273-28* 


PRELIMINARY  COURSE  LECTURES. 


LECTURE    I. 


THE  INFLUENCE  OF  PHYSIOLOGY  UPON  PRAC- 
TICE AND  UPON  THE  PRACTITIONER. 


The  Address  Introductory  to  the  Course  on  Physiology  at  the  Medical 
College  of  Ohio,  September  1,  1878. 


C  ONTENTS. 

Dr.  Jacob  Primrose — The  Exercitatio  de  Motu  Cordis,  etc. — Science  vs. 
Practice — The  Fallacy  of  Experience — Some  Old  Receipts — Opinions 
of  Noted  Men — Sterne,  Shakespeare  and  Moliere — The  Roj-al  Touch 
and  the  Caul — Contributions  of  Physiology  to  Practice — The  Uni- 
versity of  Naples — The  Modern  Physician — Gladstone's  Response 
— Harvey  and  Haller — Characteristics  of  Physiologists. 

Nobody  in  this  hall  ever  heard,  I  venture  to  say,  of  Dr. 
Jacobus  Primerosius.  But  Primrose  made  a  good  deal  of 
noise  in  his  day,  and  many  were  they  who  thought  him  a 
great  physician.  I  pick  out  Primrose  to-night  from  among 
all  the  notabilities  of  his  time  because  he  was  a  representative 
man.  He  made  himself  the  exponent  of  his  class.  When 
the  immortal  Harvey  proclaimed  that  startling  truth  about 
the  circulation  of  the  blood,  which  electrified  the  every-day 
world  as  well  as  the  world  of  science  and  our  branch  of  it  to 
such  degree  that  physicians  met  in  counsel  and  gravely 
looked  in  each  others  faces  and  distressedly  asked  "what  is 
now  to  become  of  us?"  Primrose  arose  and  said :  "Pah !  The 
Ancients  made  good  cures  before  Harvey  was  born." 

Thereupon  Primrose  proceeded  to  put  Harvey  down. 
Harvey  had  worked  twenty  years  over  his  study  before  he 


2  HARVEY'S  WORK. 

could  solve  it  to  his  own  satisfaction.  Then  only  did  he 
preach  his  doctrine.  He  worked  on  nine  years  more.  He 
repeated  all  his  old  experiments.  He  made  new  ones.  He 
called  in  all  his  friends  whom  he  considered  competent  and 
secured  their  confirmation.  Then  only  did  he  publish  it. 
Harvey  was  fifty  years  old,  it  was  in '1628,  when  he  pub- 
lished this  first  and  of  all  the  most  brilliant  triumph  of  ex- 
perimental physiology.  It  was  written  in  the  purest  spirit 
of  science,  expressed  with  an  accuracy  the  most  rigid  and 
impressed  with  a  modesty  all  through  it  in  accord  with  its 
title.    He  called  it 

"An  Attempt." 

It  was  only  a  short  manuscript,  seventy-two  pages  in  all,  a 
fact  in  itself  which  put  it  in  wonderful  contrast  to  the 
gigantic  folios  of  speculation  composed  at  that  time.  There 
is  a  spirit  of  reverence  all  through  it  for  the  labors  of  his 
predecessors,  especially  for  those  of  Galen.  It  lies  now,  the 
original  paper,  upon  the  shelves  of  the  British  museum; 
as  to  the  truths  contained  in  it,  what  child  but  knows  that 
its  heart  beats  with  pulses  of  blood.  There  followed  after 
Harvey  in  later  years  the  next  great  man  in  physiology. 
This  man,  a  Swiss,  Albert  Haller  by  name,  said  of  Harvey : 
"His  name  is  second  only  to  Hippocrates."  "Libellus  aureus" 
he  said  of  his  book. 

Primrose  felt  towards  Harvey,  the  keen  envy  of  ignorance 
and  pretense  towards  solid  knowledge  and  sound  truth.  He 
hurried  out  his  book  under  a  high-sounding  title  in  just 
fourteen  days.  The  same  Haller  said  of  it:  "It  is  subtle  in 
cavil,  in  experiment  empty."  Harvey  never  noticed  it 
at  all. 

I  would  like  to  use  this  incident  in  illustration  of  the  sub- 
ject of  my  theme.  Had  the  respective  studies  of  these  two 
men,  Primrose  and  Harvey  (I  will  scarcely  be  pardoned  now 


SCIENCE   VS.    TRACTICE.  3 

for  mentioning  their  names  together),  anything  to  do  with 
their  characters  as  men  and  physicians. 

Besides  this  vindication  of  the  study  of  physiology  I  would 
like  to  use  the  opportunity  to  speak  of  the  influence  of 
physiology  upon  practical  medicine  as  well  as  upon  the  status 
of  the  medical  practitioner. 

Science  vs.  Practice. 

It  may  seem  strange  to  the  non-professional  observer  that 
there  could  be  any  possible  question  as  to  the  general  use  of 
physiology.  A  man  would  hardly  entrust  his  watch  for  re- 
pair to  an  operator  who  was  not  familiar  with  its  mechanism 
and  the  manner  of  its  work  when  in  good  working  order, 
but  there  are  those  in  the  profession  now,  hard  as  it  sounds, 
just  as  there  were  in  Harvey's  day,  who  believe,  or  affect  to 
believe,  that  scientific  investigation  unfits  a  man  for  practice. 
John  Aubrey,  who  was  at  Harvey's  funeral  and  "helpt  to 
carry  him  into  the  vault,"  writes :  '*T  have  heard  him 
(Harvey)  say,  that  after  his  booke  of  the  Circulation  of  the 
Blood  came  out,  he  fell  mightily  in  his  practice,  and  t'was 
believed  by  the  vulgar  that  he  was  crack-brained ;  and  all 
the  physitians  were  against  his  opinion  and  enoyed  him. 
All  his  profession  wTould  allow  him  to  be  an  excellent 
anatomist,  but  I  never  heard  of  any  that  admired  his  thera- 
peutique  way.  I  knew  several  practitioners  in  this  town 
(London)  that  would  not  have  given  3d.  for  one  of  his  bills 
(prescriptions),  and  that  a  man  could  hardly  tell  by  one  of 
his  bills  what  he  did  aime  at."  We  shall  see  shortly  how 
much  to  be  admired  was  the  "therapeutique  way"  of 
Harvey's  contemporaries. 

It  is  meet  that  we  should  consider  these  questions  now 
while  we  stand  on  the  threshold.  If  we  can  become  fully 
convinced  of  the  use  of  its  study  we  shall  enter  with  more 


4  THE   FALLACY   OF   EXPERIENCE. 

earnest  zeal.  Nothing  so  dampens  enthusiasm,  so  hampers 
progress,  as  doubt  of  the  utility  of  the  work. 

I  might,  if  I  chose,  content  myself  with  merely  pointing 
to  the  discovery  of  the  circulation,  the  event  which  marked 
a  new  era  in  practical  medicine.  The  skeptic  must  shut  his 
eyes  on  this  discovery  before  he  can  discuss  the  question 
at  all. 

Is  there  any  disease  or  accident  incident  to  man  in  the 
recognition  or  treatment  of  .which  we  do  not  hold  this  ele- 
ment in  mind  like  letters  of  the  alphabet  in  reading  the 
page.  Take  coarser  facts.  Could  any  one  diagnosticate 
the  character  of  a  valve  disease  of  the  heart  without  a 
knowledge  of  the  round  of  the  circulation.  Does  not  the 
treatment  of  wounded  arteries  or  diseased,  as  in  aneurism,  by 
placing  ligatures  on  the  vessels  between  the  heart  and  tne 
accident  or  disease  rest  upon  this  established  course  of  the 
torrent  of  blood.  "The  active  mind  of  John  Hunter,"  says 
Mr.  Hodgson,  "guided  by  a  deep  insight  into  the  powers  of 
the  animal  economy,  substituted  for  a  dangerous  and  un- 
scientific operation,  an  improvement  founded  upon  a 
knowledge  of  those  laws  which  influence  the  circulating 
fluids  and  absorbent  system ;  and  few  of  his  brilliant 
discoveries  have  contributed  more  essentially  to  the  benefit 
of  mankind." 

But  I  do  not  wish  to  rely  for  our  foundation  simply  upon 
the  great  corner  stone.  I  would  rather  upon  this  occasion 
enter  into  some  details  that  you  may  be  impressed  the 
more  firmly,  that  rational  practice  is  based  on  the  dis- 
closures of  physiology,  that  you  may  be  convinced  that  the 
art  of  medicine,  practice,  is,  or  is  fast  becoming,  but  a 
dependent  upon  its  science,  physiology. 

The  Fallacy  of  Experience. 
Before  any  knowledge  was  possessed  of  the  physiological 


THE  FALLACY   OF   EXPERIENCE.  6 

action  of  medicines,  disease  could  only  be  treated  by  em- 
piricism. Experience  was  the  great  physician.  See  how 
blindly  experience  worked.  Suppose  1  should  read  you  a 
few  receipts  from  the  prescription  books  of  some  of  the 
notabilities  of  their  times,  times  close  about  that  of  the 
discovery  of  the  circulation.  It  is  the  age  of  Shakespeare, 
of  Francis  Bacon,  luminaries  so  glorious  in  literature  and 
philosophy  that  there  is  still  no  defalcation  in  the  lustre  of 
their  rays.  And  who  was  the  representative  man  in  medi- 
cine in  that  illustrious  day?  Theophrastus  Paracelsus 
Bombastus.  A  name  which  has  become  the  synonim  of  the 
grossest  charlatany.  He  it  was,  who  openly  ridiculed  all 
scientific  investigation,  who  publicly  burned  the  works  of 
Galen  and  Avicenna  and  boasted  that  he  treated  disease  by 
his  superior  intuitive  knowledge.  Maxwell,  Greatrake, 
Digby,  foremost  men  at  this  time,  were  theosophic  enthusiasts 
who  regarded  diseases  as  the  consequence  of  sin  and  the 
work  of  demons.  It  was  the  age  of  conjury  and  witch- 
craft and  priestcraft.  It  was  the  period  of  the  so-called 
ont61ogical  conception  of  disease.  Diseases  were  peculiar 
beings  or  things  with  special  properties  or  powers  which 
had  to  be  exorcised  or  conjured  away.  This  doctrine  held 
sway  long  aftet  Harvey's  day.  It  was  only  when  the 
natural  functions  of  organs  had  been  fully  described  that 
the  present  physiological  view,  that  disease  proceeded  from 
lesion  of  structure  or  function,  was  developed.  So  in  the 
olden  time  there  were  special  formulas  for  special  diseases. 
Bulleyn  prescribed  for  a  young  child,  suffering  with  some 
nervous  disease,  "a  small  young  mouse  roasted."  Sterne 
writes :  "My  physicians  have  almost  poisoned  me 
with  what  they  call  bouillons  refraichissants.  'Tis  a  cock 
flayed  alive  and  boiled  with  poppy  seeds,  then  pounded  in 
a  mortar  and  afterwards  passed  through  a  sieve.  There 
is  to  be  one  craw-fish  in  it,  and  I  was  gravely  told  it  must 


6  THE   FALLACY   OF   EXPERIENCE. 

be  a  male  one  ;  a  female  would  do  me  more  hurt  than  good." 
Of  one  receipt,  a  regular  salmagundi,  from  the  Elizabethan 
age,  its  author  remarks :  "To  tell  the  virtues  of  this  water 
against  colds,  phlegme,  dropsy,  heaviness  of  mind,  coming 
of  melancholy,  I  cannot  at  this  present,  the  excellent  virtues 
thereof  are  such,  and  also  the  time  were  too  long."  Of 
another  which  contained  gold  and  silver,  sapphires  and 
pearls,  with  spices  and  various  perfumes :  "This  healeth 
cold  diseases  of  ye  brain,  heart,  stomach.  It  is  a  medicine 
proved  against  the  tremblyings  of  the  heart,  fainting  and 
swooning,  the  weakness  of  ye  stomacke,  pensiveness,  soli- 
tariness. Kings  and  noble  men  have  used  this  for  their 
comfort.  It  causeth  them  to  be  bold-spirited,  the  body  to 
smell  well  and  engendereth  good  colour." 

Even  up  to  less  than  fifty  years  ago  they  bled  patients 
for  the  cure  of  consumption.  In  the  annals  of  Louis  XIV, 
two  centuries  ago,  is  an  account  of  the  illness  with  con- 
sumption of  one  of  the  principal  ladies  of  the  court.  On 
consultation,  the  doctors  bled  her  in  the  arm.  Next  week 
they  bled  her  again,  this  time  in  the  temple.  Strange  to 
relate  she  was  still  worse  on  the  following  week,  and  the 
consultation  was  more  anxious  still.  But  there  were  re- 
sources in  medicine  in  the  days  of  the  great  emperor.  The 
doctors  bled  her  again,  this  time  in  the  toe !  They  never 
bled  her  any  more. 

Small-pox  was  treated  in  accordance  with  the'  doctrine  of 
signatures.  The  bed  covers  were  red  to  bring  the  pustules 
to  the  surface.  The  bed  furniture  and  bed-hangings  were 
all  red,  and  red  substances  were  to  be  looked  upon  by  the 
patient.  The  very  drinks  were  red.  John,  of  Gaddesden, 
physician  to  Edward  II,  directed  his  patients  to  be  wrapped 
up  in  scarlet  dresses ;  and  he  says  that  when  the  son  of  the 
renowned  King  of  England  (Edward  II)  lay  sick  of  the 
small-pox  I   took  care  that  every  thing  around  the  bed 


OPINIONS   OF  NOTED   MEN.  7 

should  be  of  a  red  color,  which  succeeded  so  completely 
that  the  prince  was  restored  to  perfect  health  without  a 
vestige  of  a  pustule  remaining.  About  the  middle  of  the 
seventeenth  century,  the  doctrine  of  signatures  was  sub- 
stituted by  the  system  of  expelling  the  peccant  humors  by 
the  perspiration.  We  have  a  fine  picture  of  this  practice 
in  the  writings  of  Diemerbroeck,  a  Dutch  physician  and 
Professor.  "Keep  the  patient,"  says  Diemerbroeck,  "in  a 
chamber  close  shut.  If  it  be  winter  let  the  air  be  corrected 
by  large  fires.  Take  care  that  no  cold  gets  to  the  patient's 
bed.  Cover  him  over  with  blankets.  Red  blankets  have 
always  been  preferred — not  that  the  color  is  material,  but 
because  in  the  times  of  our  ancestors  all  the  best,  thickest 
and  warmest  blankets  were  dyed  red.  Never  shift  the 
patient's  linen  till  after  the  fourteenth  day,  for  fear  of 
striking  in  the  pock  to  the  irrecoverable  ruin  of  the  patient. 
Far  better  it  is  to  let  the  patient  bear  with  the  stench  than 
to  let  him  change  his  linen  and  thus  be  the  cause  of  his  own 
death.  Nevertheless,  if  a  change  be  absolutely  necessary, 
be  sure  that  he  puts  on  the  foul  linen  that  he  put  off  before 
he  fell  sick,  and  above  all  things,  be  sure-that  this  semi-clean 
linen  be  well  warmed.  Sudorific  expulsives  are  in  the 
meantime,  to  be  given  plentifully,  such  as  molasses, 
pearls  and  saffron." 

Fantastic  and  nauseous  things  were  used  in  the  treatment 
of  disease,  the  raspings  of  a  skull  for  epilepsy,  lizards,  the 
excretions,  etc.,  ad  nauseam. 

Opinions  of  Noted  Men. 

Is  it  any  wonder  that  the  shrewd  author  of  Tristam  Shandy 
should  express  his  opinion  of  medicine  and  medical  men  in 
the  manner  in  which  he  spoke  of  his  treatment  at  the  hands 
of  the  physicians  of  his  day :  "I  was  ill  of  an  epidemic  vile 
fever,"  he  writes,  "which  killed  hundreds  about  me.    The. 


8  OPINIONS  OF   NOTED  MEN. 

physicians  here  are  the  erran test  charlatans  in  Europe  or  the 
most  ignorant  of  all  pretending  fools.  I  withdrew  what  was 
left  of  me  out  of  their  hands  and  recommended  myself  en- 
tirely to  Dame  Nature.  She  (gentle  goddess)  has  saved  me 
in  fifty  different  pinching  bouts,  and  I  begin  to  have  a  kind 
of  enthusiasm  now  in  her  favor,  and  in  my  own,  that  one  or 
two  more  escapes  will  make  me  believe  I  shall  leave  you  all 
at  last  by  translation,  and  not  by  death."  Is  it  any  wonder 
that  a  man  of  Shakespeare's  penetration  (Shakespeare  had 
been  dead  three  years  when  Harvey  announced  his  discovery) 
should  depict  for  us  his  Dr.  Caius  in  the  Merry  Wives  of 
Windsor  as  a  boisterous,  blustering,  ignorant  knave,  his  Dr. 
Pinch  in  the  Comedy  of  Errors  as  a  poor  fool  whose  beard  is 
singed  by  an  indignant  patient,  and  whose  sacred  person  is 
defiled  by  "great  pails  of  puddled  mire."  Is  it  any  wonder 
that  he  should  tell  his  people,  in  another  place,  what  to  do 
with  physic ! 

"Believe  me,"  said  Napoleon  to  Antomarchi,  his  physician 
at  St.  Helena,  "we  had  better  leave  off  all  these  remedies. 
Life  is  a  fortress  which  neither  you  nor  I  know  anything 
about.  Why  then  throw  obstacles  in  the  way  of  its  defense  ? 
Its  own  means  are  superior  to  all  the  apparatus  of  your 
laboratories.  Corvisart  candidly  agreed  with  me  that  all 
your  filthy  mixtures  are  good  for  nothing.  Medicine  is  a 
collection  of  uncertain  prescriptions,  the  results  of  which, 
taken  collectively,  are  more  fatal  than  useful  to  mankind. 
Water,  air,  cleanliness,  are  the  chief  articles  in  my  pharma- 
copeia." Moliere  most  keenly  satirised  the  credulity  of  his 
time  in  medical  matters  when  he  wrote :  "11  ne  faut  pas 
mourir  sans  Vordonnance  du  medicin"  (Let  no  one  dare  to  die 
without  drugs  from  the  doctor).  Poor  Moliere  fell  upon 
the  stage  suffocated  with  hemoptysis,  in  the  midst  of  his 
bitterest  tirade  against  medical  men.  Whereupon  an  old 
physician  remarked :  "Faitcs  des  comedies  contre  nous  si  vous 


THE   ROYAL  TOUCH.  9 

voulez;  metis  la  medecine  vous  defend  dc  les  jouer  sous  peine  de 
la  vie." 

The  Hoyal  Touch. 

Who  lias  not  heard  of  the  glory  and  the  grandeur  of  the 
reign  of  Louis  XIV  ?  How  few  of  us  know  of  the  abject 
misery  and  horrible  disease  which  all  this  glory  and  grandeur 
cost.  History  is  full  of  its  pomp  and  its  ceremony.  Let  us 
read  but  one  page  of  its  ignorance  and  credulity. 

The  day  is  Sunday  in  early  spring,  Easter  Sunday.  168G. 
The  grand  monarch  is  on  the  throne.  Around  him  are  the 
tapestries  and  clothes  of  gold,  the  rich  hangings,  the  polished 
floors,  mosaics,  marbles,  gold  and  precious  stones.  About 
him  stand  obsequeous  countiers.  Behold  the  King  by  the 
grace  of  God ! 

One  thousand  six  hundred  miserable  wretches  are  crowded 
together  outside  the  door.  These  are  not  subjects  come  to 
do  homage  at  the  foot  of  the  throne.  They  are  the  maimed 
of  limb,  the  blear  eyed,  the  ulcerated.  Shakespeare  saw  a 
crowd  once  like  them ;  they  were,  he  says,  "strangely  visited 
people,  all  swol'n  and  ulcerous,  pitiful  to  the  eye,  the  mere 
despair  of  surgery."  They  are  come  to  the  King  to  be 
touched  for  the  King's  evil,  to  be  cured  by  being  touched. 
What  a  picture  this  for  the  artist ;  the  might  and  the  splen- 
dor of  majesty  on  the  one  hand,  the  loathsomeness  and  the 
degradation  of  disease  on  the  other ! 

Touching  for  the  King's  evil  was  not  confined  to  France. 
The  numbers  subjected  to  it  during  the  reign  of  Charles  II 
were  almost  incredible.  The  King  had  more  patients,  it  was 
said,  than  all  the  physicians  of  his  realm.  The  eagerness  to 
obtain  tickets  of  entry  was  such  that  in  Evilyn's  diary, 
March  28,  1G84,  it  is  written:  "There  was  so  great  a  con- 
course of  people,  men,  women  and  children,  to  be  touched 
for  the  evil  that  six  or  seven  were  crushed  to  death  at  the 


10  THE   CAUL. 

door.  Yet,  according  to  statistics,  more  people  died  of  scrofula 
in  this  reign  than  in  any  other  period,  probably  from  neg- 
lect of  all  proper  treatment.  March  30,  1714,  Queen  Anne 
touched  200  persons,  among  whom  was  the  celebrated  lexi- 
cographer, Dr.  Samuel  Johnson,  the  most  remarkable  ex- 
ample, perhaps,  of  the  utter  failure  of  the  cure.  Yet  Jeremy 
Collier,  in  his  Ecclesiastical  History  of  Great  Britain,  speak- 
ing of  the  many  virtues  and  miraculous  powers  of  Edward 
II,  says  "that  this  prince  cured  the  King's  evil  is  beyond 
dispute.  He  not.  only  cured  it,  but  transmitted  the  power 
of  doing  so  as  a  hereditary  miracle  to  all  his  successors.  To 
dispute  this  matter  of  fact,"  he  continues,  "is  to  go  the  excess 
of  skepticism,  to  deny  our  senses  and  be  incredulous  even  to 
ridiculousness." 

This  author  tells  us  of  a  Roman  Catholic  thus  cured  by 
Queen  Elizabeth,  who  saidj  on  being  asked  about  it,  that  "he 
was  now  satisfied  by  experimental  proof  that  the  Pope's 
excommunication  of  her  majesty  signified  nothing,  since  she 
still  continued  blessed  with  so  miraculous  a  quality"  (Petti- 
grew).  This  was  the  testimony  of  a  learned  man  of  his  day. 
Where  is  there  now  such  a  fool  as  to  believe  in  the  value  of 
a  royal  touch  ? 

The  Caul 

One  of  the  most  ridiculous,  though  perfectly  innocent,  of 
medical  superstitions,  which  is  worthy  of  mention  because 
it  is  still  cherished  by  the  illiterate  everywhere,  is  connected 
with  the  fragment  of  membrane  sometimes  born  over  a 
child's  face,  commonly  known  as  a  caul.  This  superstition 
has  existed  from  the  earliest  times  and  the  various  imaginary 
virtues  attributed  to  it  have  differed  with  every  time  and 
place.  It  is  mentioned  in  the  fourth  century  by  Aelius 
Lampidius  in  his  life  of  the  Emperor  Antoninus.  Majolus 
attributes  to  the  Roman  lawyers  the  belief  that  the  possesion 


CONTRIBUTIONS   OF   PHYSIOLOGY.  11 

of  a  child's  caul  would  make  tliem  eloquent  and  triumphant. 
It  is  spoken  of  by  St.  Chrysostom.  In  France  it  is  an  old 
superstition.  Eire  ne-  coiffl,  "to  be  born  with  a  caul,"  has 
always  been  considered  a  favorable  omen.  In  Scotland  it  is 
called  the  holy  hood.  It  is  .stated  by  Grose,  that  a  person 
possessed  of  a  caul,  may  know  the  state  of  health  of  the 
party  who  was  born  with  it ;  if  alive  and  well,  it  is  firm  and 
crisp  ;  if  dead  or  sick,  relaxed  and  flaccid.  In  former  days, 
the  caul  was  the  perquisite  of  the  midwife  who  often  traded 
upon  the  privileges  it  was  supposed  to  confer  upon  the 
owner  as  a  charm  against  drowning.  As  much  as  $150.00 
has  been  paid  for  a  caul.  The  London  Times,  of  May  8, 
1S48,  contained  the  following:  "For  sale,  a  child's  caul. 
Price  six  guineas.  Apply  at  the  bar  of  the  Tower  Shades, 
Tower  Street,  London.  The  above  article,  for  which  fifteen 
pounds  was  originally  paid,  was  afloat  with  its  late  owner 
thirty  years,  in  all  the  perils  of  a  seaman's  life  and  the 
owner  died  at  last  at  the  place  of  his  birth."  A  child's  caul 
was  advertised  for  sale  in  the  Bristol  Times  and  Mirror, 
September  30,  1874.  The  irrepressible  Hood  seems  to  have 
been  fully  aware  of  the  popular  recognition  of  its  value 
which  he  combats  in  the  tragic  event  which  subsequently 
happened  to  its  possessor. 

"But  still  that  jolly  mariner 
Took  in  no  reef  at  all, 
For  in  his  pouch  confidingly 
He  wore  a  baby's  caul." 

Contributions  of  Physiology. 

Look  with  what  tenacity  the  physicians  of  the  empiric 
school  clung  to  venesection.  Long  after  they  dared  not 
practise  it  they  persisted  in  preaching  it  still.  Centuries 
upon  centuries  they  put  mercury  into  a  man  in  whatever 
disease  of  the  liver,  blind  to  the  fact  that  notwithstanding 


12  CONTRIBUTIONS  OF  PHYSIOLOGY. 

its  administration  for  months  in  specific  disease  it  in  no  way 
influenced  the  hepatic  functions.  And  now  it  turns  out 
that  the  liver  after  all  was  not  the  organ  affected  in  almost 
all  the  cases.  Scarce  two  teachers  of  materia  medica  taught 
the  same  action  upon  the  heart  under  digitalis.  Why  ? 
Because  each  gave  his  own  experience.  When  regular 
physiological  experimentation  was  commenced,  it  was  not 
long  before  it  was  decided  that  it  had  only  one  action  in  all 
cases,  namely,  to  increase  the  force  of  the  heart's  action,  to 
diminish  the  frequency  of  its  pulsations  and  restore  its 
regular  rythm.  Let  the  most  prejudiced  observer  read  up 
the  action  ascribed  to  alcohol  in  fevers  in  different  works  on 
practice  before  the  physiologist  put  it  unchangeably  down. 
Here  it  is  advised  to  push  it  to  the  utmost ;  here  to  refrajn 
from  it  altogether.  Each  man  spoke  from  his  own  experi- 
ence. Comes  the  physiologist  with  his  thermometer.  Alco- 
hol lowers  the  temperature  is  the  result  of  his  experimenta- 
tion, and  the  indication  for  its  use  is  established.  The 
surgeon  used  to  cut  and  cut  out  the  facial  nerve,  leave  the 
face  paralysed  and  deformed  for  facial  neuralgia  (tic 
douloureux)  until  the  physiologist  taught  him  that  the 
facial  was  a  nerve  of  motion,  to  the  trigeminal  he  must  look 
in  disturbances  of  sensation.  And  then  he  would  cut  out 
this  nerve  down  to  its  escape  from  the  skull,  excise  the 
ganglion  of  Meckel,  until  he  was  again  taught  by  the  physi- 
ologist that  this  ganglion  was  only  a  reinforcing  organ  of 
the  sympathetic  system,  and  its  ablation  could  in  no  way 
permanently  cure  the  disease. 

"The  dangerous  disease,  to  which  many  children  have 
fallen  victims,  laryngismus  stridulus,  although  admirably 
described  by  practical  physicians,  was  never  properly  under- 
stood until  the  functions  of  the  laryngeal  nerves  were 
clearly  ascertained  and  until  it  had  been  shown  that  spas- 
modic actions  may  be  excited  by  irritation  of  a  remote  part 


CONTRIBUTIONS   OF   TTIYSIOLOGY.  13 

or  through  a  stimulus  reflected  from  the  nervous  centre.  It 
is  now  known  that  this  disease  has  not  its  seat  in  the  larynx 
where  those  spasms  occur  which  excite  so  much  alarm  for 
the  fate  of  the  patient;  but  that  it  is  an  irritation  of  a 
distant  part,  which  derives  its  nerves  from  the  same  region 
of  the  cerebro-spinal  centres  as  does  the  larynx — that  the 
afferent  nerves  of  that  part  convey  the  irritation  to  the 
centre  whence  it  is  reflected  by  certain  efferent  nerves  to  the 
muscles  of  the  larynx."  Do  not  these  remarks  bear  with 
equal  propriety  upon  epilepsy,  chorea,  hysteria  and  a  host 
of  kindred  affections  dependent  in  many  cases  upon  reflex 
stimulus,  a  factor  whose  paramount  importance  is  only  rec- 
ognised since  the  labors  of  the  physiologists  who  first  pro- 
claimed it.  How  much  advanced  would  we  stand  to-day  in 
the  management  of  gynaecological  diseases  beyond  the  time 
when  the  bloody  issue  was  treated  by  touch,  as  in  the  New 
Testament,  were  it  not  for  our  knowledge  of  ovulation  and 
its  necessary  consequence,  as  discovered  and  developed  solely 
by  physiological  investigations.  And  in  ophthalmology,  that 
department  which  Virchow  characterised  in  a  late  address 
before  the  British  Medical  Association  as  "that  branch-  of 
medical  science  which  has  now  reached  the  highest  degree 
of  scientific  surety,"  how  sensibly  has  treatment  developed 
under  the  physiological  investigations  into  the  functions  of 
different  parts  of  the  eye.  Helmholtz,  as  is  well  known,  and 
Grsefe,  forsook  all  other  studies  to  work  up  the  physiology 
of  vision,  and  to  these  two  observers,  more  than  all  others, 
are  we  indebted  for  the  "scientific  surety"  which  charac- 
terises practical  ophthalmology.  So  I  might  continue  for 
an  hour  and  yet  fail  to  enumerate  the  direct  contributions 
of  physiology  to  practical  medicine  within  the  past  few 
years. 

But  if  I  should  desire  to  put  physiology  in  its  proper  light 
I  should  have  to  look  out  beyond  the  mere  technical  details 


14  CONTRIBUTIONS   OF   PHYSIOLOGY. 

of  direct  contributions  in  the  immediate  treatment  of  dis- 
ease. It  would  then  be  my  pleasant  duty  to  point  out  those 
investigations  undertaken  to  unlock  the  mystery  of  the 
causes  of  disease  and  their  dissemination  by  parasitic  germs. 
I  should  have  to  linger  more  than  my  time  upon  the  influ- 
ence of  the  nervous  system  upon  all  the  vegetative  functions 
as  well  as  upon  the  circulation.  I  should  have  to  dwell 
with  that  care,  which  the  intense  interest  of  the  subject 
demands,  upon  those  recent  experiments  of  exposing  and 
irritating  certain  parts  of  the  brain  in  the  now  partially 
successful  attempt  at  a  localisation  of  its  functions  and  upon 
those  electrical  changes  observed  in  a  living  nerve  when 
sentient  impressions  are  transmitted  through  its  course,  dis- 
coveries all  of  them  whose  practical  importance  in  the 
future  no  prophecy  may  now  fortell.  It  would  be  my 
privilege  further  to  reach  out  into  broader  regions  still.  It 
is  only  in  our  day  that  the  importance  of  physiology  is  fully 
recognised  in  a  sanitary  point  of  view.  "In  their  appre- 
hensions of  epidemics,  men  are  beginning  to  bend  before 
the  shrine  of  science  and  to  recognise  the  fact  that  it  is  in 
a  patient,  persevering,  hopeful  applications  of  the  faculties 
of  investigation,  which  have  been  given  them,  rather  than 
in  any  direct  interpositions,  that  they  are  to  look  to  Provi- 
dence for  security." 

It  is  physiology  which  has  been  the  chief  agent  in  raising 
medicine  from  an  art  into  a  science.  So  far  as  the  treat- 
ment of  disease  is  concerned,  or  the  recognition  of  its  nature, 
we  have  no  other  way  to  arrive  at  the  action  of  remedies  or 
lesions  of  structure  than  through  the  portals  of  physiology. 
I  might  illustrate  this  fact,  besides  by  the  agents  already 
referred  to,  in  no  way  more  clearly  than  by  allusion  to  the 
really  wonderful  results  following  the  administration  of 
ergot  and  its  active  principle  after  its  mode  of  action  had 
been  fully  established  by  the  physiologist.    And  this,  too, 


THE   MODERN   PHYSICIAN".  15 

when  there  had  been  previously  such  a  diversity  Of  opinion 
concerning  its  action  as  to  practically  abolish  it  from  general 
use.     Pathology  is  only  the  physiology  of  disease. 

It  is  physiology  which  distinguishes  regular  medicine 
from  charlatanry.  Together  with  the  other  natural  sciences 
it  gives  evidence  which  is  positive,  immutable.  Theories 
about  fever  may  be  limited  only  by  the  number  of  those 
who  choose  to  express  an  opinion,  but  there  is  only  one 
interpretation  to  the  circulation  of  the  blood,  the  action  of 
a  nerve,  the  constitution  of  a  secretion.  It  is.  physiology, 
thus,  chiefly,  which  lifts  off  the  mist  and  the  mystery  of 
dogma  and  puts  medicine  on  the  basis  of  other  natural 
sciences,  so  that  it  may  be  proven  like  them  by  evidence 
before  all  the  cultivated  senses.  So  when  physiology  be- 
comes a  perfect  science,  should  that  day  ever  be,  there  can 
no  more  be  quackery  in  medicine  than  in  machinery.  "When 
the  question  of  the  propriety  of  introducing  homoeopathy 
into  the 

Medical  School  of  Naples 

was  presented  to  the  faculty  a  few  years  ago,  the  following 
characteristic  reply  was  tendered :  "The  University  of 
Naples  is  not  a  proper  field  for  instruction  in  homoeopathy, 
because  the  rational  medicine  which  is  imparted  here,  on  the 
basis  of  the  natural  sciences,  excludes  allopathy,  as  well  as 
homoeopathy,  or  any  other  absolute  system  or  dogma.  The 
study  of  rational  medicine  is  as  far  removed  from  the  ancient 
allopathy,  with  its  blood-letting  and  purgation,  as  from  the 
recent  delusion  of  homoeopathy,  with  its  ridiculous  infinitesi- 
mal doses  and  similia  similibus  medication." 

The  Modem  Physician. 

This  revolution  in  the  study  an.d  practice  of  medicine  has  not 
passed  unobserved  in  the  outside  world.     It  has  changed  the 


16  THE  MODERN  PHYSICIAN. 

whole  social  status  of  the  physician.  Even  as  late  as  the  J  5th 
century  an  apprentice  would  not  be  accepted  in  any  of  the 
mechanical  arts  unless  he  could  prove  that  he  was  not  the 
child  of  a  butcher,  executioner  or  a  bleeder.  The  following 
old  time  advertisement  clipped  from  a  paper  of  Shakespeare's 
day  thoroughly  establishes  the  position  of  the  every-day 
practitioner  at  that  period:  "Wanted. — In  a  family  who 
have  had  bad  health,  a  sober  steady  person  in  the  capacity 
of  doctor,  surgeon  and  man  mid-wife.  He  must  occasionally 
act  as  butler  and  dress  hair  and  wigs.  He  will  be  required 
sometimes  to  read  prayers  and  to  preach  a  sermon  every 
Sunday.  A  good  salary  will  be  given."  The  modern 
dramatist,  if  he  would  reflect  the  sentiment  of  the  people, 
exhibits  the  doctor  in  a  role  very  different  from  the  old 
time  cunning  knave  or  ignorant  charlatan.  A  moaern 
novel  is  scarcely  perfect  without  a  modern  medical  character. 
Witness,  more  especially,  the  best  works  of  Bulwer  and 
George  Eliot.  The  chord  so  feelingly  struck  by  the  master 
hand  of  Lever  has  responded  full  and  as  feelingly  to  the 
magic  touches  of  Dickens  and  Thackery.  The  physician  is 
called,  like  Haller,  to  the  chief  position  among  the  chairs  of 
state.  His  profession  is  recognised  by  the  highest  civil 
authorities.  Said  Mr.  Gladstone  in  a  recent  response  :  "and 
speaking  of  the  body  cf  the  profession,  even  as  an  observer 
from  without,  it  is  impossible  for  us  not  to  notice  the  change, 
it  is  impossible  for  us  not  to  see  how  far  more  strongly  now 
than  of  old,  the  medical  man  of  to-day  conforms  to  those 
general  laws  of  common  sense  and  prudence,  which  are,  after 
all,  universal  laws  of  human  life  in  every  one  of  its  depart- 
ments. It  is  impossible  not  to  see  his  greater  and  more 
sustained  earnestness  of  purpose,  that  elevated  sense  of 
the  professional  dignity,  that  desire  to  make  it  subservient 
to  the  good  of  humanity,  that  general  exaltation  of  his  aims 
in  the  exercise  of  his  profession." 


WILLIAM   HARVEY.  17 

And  what  is  it  that  has  thus  lifted  up  the  character  of 
the  physician  in  the  eyes  of  his  fellow-men  ?  It  is  because 
the  modern  science  of  medicine  is  supported  by  the  same 
kind  of  evidence  as  any  other  science.  Evidence  which 
may  be  sifted  by  instruments  of  precision,  evidence  which 
is  tangible,  demonstrable,  indisputable.  Such  evidence  i3 
plain  to  the  common  understanding  in  whatever  pursuit  of 
life.  It  is  evidence,  to  repeat  the  language  of  the  dis- 
tinguished statesman  just  cited,  which  conforms  to  those 
general  laws  of  common  sense,  after  all,  the  universal  laws 
of  human  life  in  every  one  of  its  departments. 

I  do  not  know  how  I  could  better  exhibit  the  influence 
of  the  study  of  physiology  than  by  a  very  brief  narration 
of  some  of  the  principal  incidents  in  the  lives  of  the  two 
greatest  of  physiologists,  Harvey  and  Haller,  already 
cited.  With  both  physiology  wras  a  life  study.  Each  is 
known  in  medical  history  as  having  contributed  a  discovery 
by  means  of  which  we  are  chiefly  guided  in  the  treat- 
ment of  disease;  Harvey's,  the  circulation;  Haller' s,  the 
knowledge  that  disease  depends  on  lesion  of  structure  or 
function. 

William  Harvey.— 1578-1658. 

Harvey  was  the  oldest  in  a  family  of  nine  children.  His 
parents  belonged  to  the  respectable  middle  class  of  society, 
that  class  from  which  has  emanated,  as  is  statistically 
proven,  the  greatest  number  of  great  men.  With  the  rest 
of  the  family,  he  had  that  kind  of  training,  which  instils 
those  virtues  in  childhood  life,  obedience  and  respect  to 
authority  and  order,  so  characteristic  of  the  English  race, 
and  without  which  excellence  can  be  attained  in  no  pursuit 
in  life.  With  these  traits,  industry.  That  was  all.  But 
that  is  always  enough.  After  leaving  Cambridge,  at  the  age 
of  21,  he  went  to  Padua  to  study  under  the  great  Fabricius, 


18  WILLIAM  HARVEY. 

who  gave  him  the  first  clue  to  his  discovery  by  show'ng 
him  the  valves  in  the  veins.  What  were  these  valves  for? 
It  was  no  flash  of  inspiration  that  answered  this  question 
for  Harvey.  It  was  solved,  as  has  been  stated,  only  after 
twenty  years  of  patient,  earnest  toil.  It  was  only  the  fact 
of  his  reputation  as  a  worker  that  secured  him  any  recogni- 
tion at  all  at  first.  But  there  was  a  charm  in  Harvey's 
statements  that  could  not  fail  to  win  him  followers.  It  was 
the  extreme  modesty  which  characterises  every  line.  When 
he  could,  he  would  support  the  opinions  of  those  who  had 
preceded  him.  When  the  truth  forced  him  to  differ,  he 
did  so,  but  with  a  delicacy  the  most  sensitive,  and  with  an 
array  of  proof  that  could  leave  no  doubt  of  the  correctness 
of  his  views.  There  have  been  to  this  day  no  corrections 
to  make  in  Harvey's  work,  and  there  never  since  has  been 
written  a  description  of  the  circulation  so  comprehensive, 
so  terse,  so  vivid.  He  was  a  worker  so  indefatigable  and 
his  works  were  so  full  of  results  that  he  soon  acquired 
fame.  The  work  of  an  earnest  man  is  a  synonim  with  fame. 
He  was  made  a  physician  at  St.  Bartholomew's,  a  boy  but 
20  years  of  age.  He  was  only  37 — that  was  a  youthful  age 
in  his  day — when  he  was  appointed  professor  of  anatomy 
and  surgery,  and  it  was  but  a  few  years  later  that  he 
became  body  physician  to  Charles  I.  He  lived  a  life  of  the 
greatest  simplicity  and  self-denial;  Michael  Angelo  not 
more  so.  Much  of  his  time  he  spent  in  perfect  retirement 
with  one  or  other  of  his  brothers  at  their  village  homes. 
He  declined  the  high  honor  of  the  presidency  of  the  College 
of  Physicians,  though  they  succeeded  in  persuading  him  to 
allow  his  bust  to  be  cast.  At  the  age  of  80,  writes  Haeser, 
the  historian,  he  closed  a  life  which  had  not  been  less 
glorious  by  the  magnitude  of  his  scientific  labors  than  by 
his  most  rigid  sense  of  justice,  his  exceeding  gentleness 
and  amiability  of  character  and  modesty  of  manner.     "On 


ALBERT   HALLER.  19 

June  3,  1G58,  lie  died,"  said  Spengel,  Our  greatest  historian, 
"but  he  left  a  name  which  is  immortal.  It  is  a  name  which 
posterity  the  most  distant  will  never  pronounce  without 
experiencing  a  sentiment  of  veneration  and  of  gratitude. 
It  will  shine  with  equal  lustre  with  those  of  Aristotle, 
Fallopius  and  Haller.  His  industry,  his  prudence  and  his 
rare  modesty,  make  of  his  character,  eternally,  a  model,  the 
most  noble,  for  the  naturalists,  for  the  writers  of  all  peoples 
and  times." 

Albert  Haller.— -1708-1777. 

The  most  cultivated  physician  and  the  greatest  naturalist 
of  his  age  was  Albert  Haller,  of  Berne.  His  advent  upon 
the  theatre  of  action  is  characterised  as  the  illumination  of 
a  meridian  sun  upon  the  obscure  dawn  of  day.  Haller  was 
of  patrician  parents,  but  it  was  no  misfortune  to  him,  as  is 
the  rule,  and  his  subsequent  career  in  the  face  of  the  tempta- 
tions besetting  wealth  affords  an  illustrious  example  of  the 
manner  in  which  money  may  be  made  subservient  to  the 
higher  purposes  of  life.  A  puny,  delicate,  rachitic  boy,  he 
could  not  be  kept  away  from  books.  It  is  said  of  him  that 
up  to  the  age  of  nine  years  he  had  read  over  two  thousand 
biographies.  When  his  father  died,  his  education  was  com- 
mitted to  a  priest  who  attempted  to  force  his  studies  in  the 
direction  of  theology  with  the  intention  of  making  him 
wear  the  robes.  But  Haller  loved  the  teachings  of  nature 
better  than  the  wisdom  of  man,  and  the  time  which  should 
have  been  devoted  to  clerical  studies  was  spent  among  the 
flowers.  He  was  only  15  years  old,  when  he  commenced  the 
study  of  medicine  at  Tubingen.  All  the  anatomy  he  could 
learn  here  was  from  dissections  of  the  dog.  The  fame  of 
Boerhaave  and  Albinus  drew  him  to  Leyden.  Here  he 
became  such  a  favorite  with  his  teachers  that  Albinus  would 
permit  him  to  dissect  on  one  side  of   the  body   while  he 


20  ALBERT   HALLER. 

worked  on  the  other.  At  19,  he  graduated  and  commenced 
his  travels.  He  was  the  student  of  Douglas,  in  London,  in 
whom  he  inspired  such  confidence  that  he  made  Haller 
promise  to  help  him  in  his  investigations  into  the  develop- 
ment of  bone.  The  same  restless,  knowledge  seeking  spirit 
carried  him  next  to  Paris,  where  his  enthusiasm  is  said  to 
have  been  kindled  to  such  a  pitch  under  the  teachings  of 
le  Dran  and  Winslow,  that  he  stole  a  body  from  the  grave 
for  material  upon  which  to  work.  He  had  to  leave  Paris  to 
escape  punishment  and  next  we  find  him  in  Basel,  at  the 
age  of  twenty,  teaching  anatomy  to  the  students.  In  1736, 
he  was  now  28,  he  was  elected  professor  of  anatomy  and 
surgery  at  the  newly  established  university  of  Gottingen. 
Proud  of  so  early  a  recognition  of  his  talents,  he  labored  for 
the  success  of  this  institution  until  students  streamed  in  td 
the  young  college  from  all  parts  of  Europe.  He  was  now 
teaching  anatomy,  surgery  and  botany.  A  regular  chair  of 
physiology  had  not  yet  been  established.  Besides  these 
labors,  he  kept  up  his  work  in  natural  history,  wrote  a  great 
number  of  literary  papers  and  occupied  what  leisure  was 
still  left  in  composing  poetry.  At  the  age  of  45  he  was  so 
completely  broken  down  that  he  had  to  retire. from  all  active 
duties.  We  form  some  idea  of  his  "iron  industry,  his  almost 
incredible  memory,  his  profound  culture  in  all  the  branches 
of  human  knowledge"  by  the  story  which  has  come  down  to 
us  that  no  one  of  his  Gottingen  colleagues  ever  ventured  to 
visit  him  without  a  formal  preparation  upon  the  theme  to 
be  made  the  subject  of  conversation.  He  is  said  to  have 
written  12,000  reviews!  And  yet  he  never  left  a  letter 
unanswered.  According  to  all  testimony,  there  was  never  in 
medicine  a  laborer  so  untiring.  Rudolphi  naively  remarks 
in  the  preface  to  his  own  work  on  physiology :  "If  you  should 
ask  all  the  authors  of  works  on  physiology,  which  book  they 
considered  the  best,  it  could  not  be  thought  strange  if  each 


CHARACTERISTICS   OF   PHYSIOLOGISTS.  21 

one  would  reply,  his  own.  But  if  you  should  go  further 
and  ask  each  one  what  book  he  considered  next  best,  I  am 
convinced  that  every  one  without  exception  would  name 
Haller's.  And  surely,"  Rudolphi  continues,  "what  seems 
to  all  the  second  best  must  be  in  reality  the  first." 

Besides  this,  his  greatest  work,  Haller  was  the  author  of 
three  distinct  bibliographies,  of  anatomy,  surgery  and  prac- 
tical medicine,  which  have  been  characterised  as  "monu- 
ments of  his  incredible  literary  activity,  which  stand  isolated 
in  medical  literature,  and  will  remain  for  all  time  as  inex- 
haustible sources  of  information  to  the  medical  historian." 
Colin,  in  his  Comparative  Physiology,  called  Haller  "Uhomme 
desfaits,  Vhomme  de  V observation  et  des  experiences ;  son  oeuvre 
est  le  point  de  depart  de  toute  la  physiologie  moderne.  Cruveil- 
hier  spoke  of  it  as  "full  of  discoveries."  His  original  in- 
vestigations were  so  numerous  and  so  valuable,  as  to  justly 
entitle  him  to  the  place  assigned  him  by  posterity  as  the 
"Founder  of  Modern  Physiology."  The  latter  part  of  his 
life  he  spent  at  Berne  in  the  exercise  of  the  highest  civic 
powers  in  the  state,  though  even  here  he  found  leisure  to 
prosecute  his  favorite  scientific  and  literary  pursuits.  The 
sculpture  on  the  pillar  of  fame  in  history  has  chiseled  his 
name  beside  that  of  Aristotle  and  Goethe  and  Humboldt. 

Characteristics  of  Physiologists. 

And  what  then  were  the  characteristics  of  these  two  great 
physiologists?  They  were  cautious  men.  Harvey  proved 
his  study  twenty  years  before  he  preached  it.  Haller  made 
109  experiments  before  he  published  his  discovery  of  the 
independent  irritability  of  muscle.  They  were  truthful 
men.  The  bitter  opposition  of  their  contemporaries,  the 
experimentation  of  all  posterity,  have  never  shaken  the  facts 
they  advanced.  They  were  simple  men  ;  in  all  their  tastes 
and  habits ;  among  other  things  it  is  recorded  of  both,  they 


22  CHARACTERISTICS   OF  PHYSIOLOGISTS. 

were  men  of  gentle  deportment.  Above  all,  they  were 
working  men.  And  if  the  question  were  asked  as  to  the 
influence  of  the  study  of  physiology  on  the  character  of  the 
physician,  there  could  be  no  more  fitting  answer  than  a 
reference  to  the  lives  of  men  who  have  drifted  into  it  as  a 
life  study  because  of  their  natural  adaptability  to  it. 

One  point  more.  Physiology  offers  to  the  physician  a 
present  refuge  in  time  of  trial.  The  vicissitudes  of  practice, 
the  rancor  of  rivals,  the  unceasing  combat  against  prejudice 
and  ignorance  and  superstition  make  life  a  burden  at  times 
even  where  envy  marks  it  a  great  success.  It  is  in  dark 
hours  like  these,  and  who  but  knows  them,  that  the  physi- 
cian may  turn  to  the  study  of  physiology.  No  man  of  the 
world,  no  man  of  other  profession  than  natural  science,  may 
ever  know  or  be  able  to  understand  the  peace,  in  the  way  of 
fresh  inspiration  for  future  work,  which  nature  offers  at 
the  foot  of  her  altars.  The  chief  reward  of  every  kind  of 
mental  work — higher  than  either  wealth  or  fame— is  its 
effect  upon  the  character.  The  study  of  medicine  is  pe- 
culiarly excellent  in  developing  the  mental  faculties.  Hav- 
ing elements  in  it  belonging  to  both  literature  and  science — ■ 
the  bride  and  her  spouse  in  modern  education — it  most 
happily  blends  the  virtues  and  balances  the  faults,  pertain- 
ing to  a  purely  literary  or  a  purely  scientific  pursuit. 

I  should  fall  short  of  the  high  purpose  of  our  convo- 
cation, to-night,  should  I  fail  to  impress  upon  you  clearly 
the  trial  which  science  demands  at  your  hands  before  she  will 
adorn  you  with  the  stamp  of  her  nobility.  It  is  the  trial 
of  work,  the  chief  characteristic,  as  you  have  seen,  in  the 
lives  of  our  eminent  men  ;  work  with  the  sacrifice  of  self ; 
work  which  is  only  stimulated  to  higher  efforts  by  the 
achievements  of  others ;  work  with  something,  at  least,  of 
that  feeling  in  the  breast  of  Themistocles— a  poor  illegiti- 
mate boy— Euler  of  AtherTs  he  became— who  was  alone 


THE  CONSERVATION   OF  FORCE.  23 

sorrowful  and  distressed  amidst  the  general  rejoicing  over 
the  great  victory  at  Marathon.  And  when  they  asked  him 
why  his  eyes  were  red  with  weeping  and  why  he  walked 
the  streets  with  disheveled  hair,  he  made  them  that  reply 
which  foretold  his  future  success :  "It  was  the  trophies  of 
Miltiades  that  would  not  let  him  sleep." 


LECTURE    II. 
THE  CONSERVATION  OF  FOECE. 

CONTENTS. 

The  Alphabet  of  Science — Indestructibility  of  Matter— No  Matter  with- 
out Force — Solar  Origin  of  Heat  of  Coal— Correlation  of  Forces — 
Machinery,  a  Means  of  Changing  Force— Clocks,  Water-Wheels, 
Winds,  Windmills  and  Steam  Engines— The  Equivalence  of  the 
Forces — The  Conservatory  of  Arts  and  Trades— Motion  from  Heat — 
Motion  from  Electricity— The  Electric  Light— The  Sun  as  the  Source 
of  Power— Source  of  Solar  Force— The  Nebular  Hypothesis— The 
Channel  of  Mt.  Pilatus— The  Perpetuity  of  Force— Physiological 
Force — Excretions,  the  Products  of  Combustion— Animal  Bodies  as 
Machines— The  Force  Value  of  Foods— Physiological,  Correlative 
with  Physical  Force. 

Within  the  past  quarter  of  a  century  has  been  generally 
promulgated  one  of  those  fundamental  principles  or  laws  in 
natural  science  which,  like  that  of  gravitation  or  of  ter- 
restrial revolution,  marks  a  most  memorable  epoch  in  its 
history.  What  especially  distinguishes  this  law  and  lifts  it 
to  a  plane  above  all  other  laws  of  nature,  is  the  fact  that  it 
spans,  in  its  giant  grasp,  every  order  of  existence.  It 
reduces  to  shape  and  order  the  primitive  chaos  of  the  uni- 
verse, governs  the  movements  of  the  heavenly  bodies  thus 
created,  generates  the  various  forms  of  the  mighty  forces 
about  us,  and,  while  engaged  in  this  stupendous  work,  con- 


24  INDESTRUCTIBILITY   OF  MATTER. 

cerns  itself  no  less  with  the  insignificant  phenomena  of  life 
upon  our  insignificant  globe ;  swinging  systems  of  planets 
in  their  spheres,  upon  the  one  hand,  and,  on  the  other, 
springing  flowers  from  the  bosom  of  the  earth.  I  need 
hardly  say  that  this  law,  which  has  been  announced  as  the 
primal  law  of  all  science,  and  which  has  been  characterised 
by  Faraday  as  the  highest  law  in  physical  science  that  our 
faculties  permit  us  to  perceive,  is  the  law  of  the  Conservation 
and  Correlation  of  Force.  That  is,  it  is  the  law  which  has 
demonstrated  that  force,  as  well  as  matter,  is  indestructible, 
however  much  its  form  may  change,  and  which  has  proven 
that  all  the  forces,  light,  heat,  electricity,  motion,  etc.,  may 
be  converted,  the  one  into  the  other,  quantity  for  quantity, 
in  exact  equivalents,  no  force  being  ever  created  anew  and 
no  force  being  ever  lost. 

We  shall  study  this  law  to-night  more  especially  in  its 
bearing  upon  human  life,  and  shall  try  to  make  it  plain 
that  what  is  known  as  life,  or  vital  force,  is  only  part  of  the 
general  store  of  force  in  the  universe,  borrowed  for  the  time 
being  from  other  physical  forces  and  being  continually  sur- 
rendered again  in  the  various  phenomena  of  life,  as  in  heat, 
motion,  secretion,  reproduction,  intellection,  etc. 

Indestructibility  of  Matter. 

It  is  now  more  than  a  century  ago  that  it  was  known 
among  men  of  science  that  matter  is  indestructible.  When 
we  speak  of  the  destruction  of  matter,  we  refer  simply  to 
the  form  of  the  matter.  For  instance,  we  say  matter  is 
destroyed  by  fire.  But  when  we  come  to  analyse  the  pro- 
ducts of  combustion,  we  find  in  the  smoke,  the  gases  and 
the  ash  precisely  the  same  elements  as  before.  We  pro- 
ceed to  weigh  these  various  products  in  delicate  scales  to 
discover  only  pounds  and  ounces  and  grains,  just  the  same 
as  before.    Fire  has  only  changed  the  form.     So  when  wa 


SOLAR   ORIGIX   OF   HEAT.  25 

speak  of  organic  matter  suffering  destruction  by  decay,  we 
refer  again  simply  to  the  form.  The  water,  the  salts,  the 
gases  of  decomposition,  weigh  exactly  the  same,  are  in 
elementary  construction,  in  every  particular,  just  the  same 
'  as  before.     Putrefaction  has  only  changed  the  form. 

And  so,  too,  of  creation.  We  justly  boast  of  our  manu- 
factured products.  But  no  ingenuity  of  man  has  ever  suc- 
ceeded in  creating  matter  anew.  Ex  nihilo  nihil  fit.  Anni- 
hilation of  matter,  creation  of  matter  are  alike  impossible 
and  unknown. 

Now  it  is  discovered  that  there  is 

No  Matter  without  Force. 

The  force  may  not  be  always  apparent,  that  is,  it  is  not 
always  in  active  operation,  but  we  have  simply  to  change 
the  condition  of  matter  to  awaken  and  make  manifest  its 
silent  force.  Force  in  operation  is  known  as  actual  force ; 
that  which  is  silent,  at  rest,  so  to  speak,  or  latent,  is 
known  as  potential  force.  The  arrow  speeding  in  its  flight 
or  striking  its  target  represents  actual  force,  while  the  bent 
bow,  unsprung,  represents  latent  or  potential  force.  The 
force  in  the  bow  is  stored  up  muscular  force  to  be  set  free, 
it  may  be  at  once,  or  it  may  be  after  years.  Plants  now 
living  contain  recently  stored  latent  or  potential  force, 
while  coal  fields  are  vast  magazines  of  force  stored  up  ages 
ago. 

Solar  Origin  of  Heat. 

George  Stephenson,  the  celebrated  engineer,  long  ago  con- 
ceived the  happy  idea,  as  he  sat  by  his  hearth,  that  the  light 
and  heat  of  the  burning  coal  in  his  grate  originally  came 
from  the  sun.  This  thought,  which  seemed  at  the  time  to 
be  as  visionary  as  a  poet's  dream,  is  now  known  to  be  true. 
Every  one  knows  that  coal  is  a  product  of  vegetable  life. 

3 


26  SOLAR  ORIGIN"  OF  HEAT. 

A  fresh  fracture  often  reveals  upon  its  surface  the  outlines 
of  stems  and  branches  and  leaves  with  such  distinctness  as 
to  enable  the  botanist  to  specify  the  particular  plant  which 
has  formed  the  specimen  of  coal.  Vegetation  of  all  kinds 
develops  only  under  the  light  and  heat  of  the  sun.  Veget- 
able, seeds  imbedded  in  clean  sand  and  moistened  with 
water  containing  only  mineral  matters  in  solution,  germinate 
and  develop  into  plants  containing  a  large  amount  of  starch. 
The  simple  process  is  as  follows: 

Carbonic  Acid  Gas.  Water.     Oxygen.       Starch. 

C6012    +    H10O5-O12  =  C6H10O5. 

The  light  and  heat  of  the  sun,  entering  the  substance  of  the 
plant,  dislodge  a  certain  amount  of  oxygen  gas  that  the 
atoms  of  the  inorganic  compounds  may  rearrange  themselves 
to  form  organic  matter.  Starch  is  the  first  organic  principle 
of  the  plant.  The  sugar,  cellulose  and  other  ingredients 
are  easily  developed  by  the  addition  or  change  of  equivalents 
of  water.    Thus : 

Starch.        Water.        Grape  Sugar. 

C6H10O5  -f-  H20  =  CGH1206. 

Thus,  then,  is  built  up  the  plant,  the  tree,  vast  forests  of 
which  covered  the  earth  in  primeval  times  to  become  sub- 
sequently submerged  and  converted  into  coal.  In  burning 
coal  we  simply  release  from  it  the  locked  up  heat  of  the 
sun.  The  heat  and  light  we  enjoy  to-night  came  down 
from  the  sun  thousands  of  years  before  man  put  in  his  pres- 
ence upon  earth. 

No  force  is  ever  lost.  It  may  be  changed  as  to  its  direc- 
tion or  changed  as  to  its  character,  but  in  some  form  or 
other  it  perpetually  reappears.  So  all  the  affections  or  con- 
ditions of  matter,  heat,  light,  electricity,  chemical  affinity, 
motion,  etc.,  are  mutually  convertible.  Neither  can  be 
said,  strictly  speaking,  to  be  the  cause  of  the  other,  but 


MACHINERY   A   MEANS  OF  CHANGING   FORCE.  27 

either  may  be  converted  into  the  other  :  "it  being  an  irre- 
sistible inference  from  observed  phenomena  that  a  force 
caunot  originate  otherwise  than  by  devolution  from  some 
preexisting  force."  It  is,  therefore,  not  right  to  say  that 
any  one  force  is  the  cause  of  all  the  rest.  One  writer,  for 
instance,  claims  electricity  as  the  primal  cause ;  another, 
chemical  action ;  a  third,  heat ;  but  the  true  expression  of 
the  fact  is,  that  each  mode  of  force  is  capable  of  producing 
the  others,  and  that  any  one  of  them  can  be  produced  by 
any  other. 

Machinery  a  Means  of  Changing  Force. 

"We  may  best  exemplify  the  conversion  and  correlation 
of  force  by  the  transmutations  which  take  place  in  various 
kinds  of  machinery.  In  fact,  machinery  is  only  a  means 
of  effecting  change  in  the  form  of  force.  Thus  in 
our  clocks,  the  wheels  which  sweep  the  hands  around  the 
dial  plates  are  revolved  by  sinking  weights.  When  the 
weights  reach  the  floor  of  the  clock  the  wheels  cease  to 
move.  In  other  wrords,  the  force  of  gravity  ceases  to  act. 
We  must  first  raise  the  weights,  or,  in  the  case  of  a  watch, 
give  tension  to  the  springs,  before  the  wheels  will  run.  This 
is  accomplished  in  the  winding  up.  The  individual  wrho 
winds  the  clock  simply  transfers  power  from  his  muscular 
force  and  precisely  so  much  as  is  thus  transferred  is  again 
surrendered  in  the  ensuing  twenty-four  hours.  The  wheel 
work  of  the  clock,  in  measuring  out  time,  creates  or  exhibits, 
therefore,  no  new  force  ;  it  simply  distributes  a  borrowed 
force  over  a  longer  period  of  time.  The  borrowed  force 
is  that  of  the  muscle,  which  receives  it,  in  turn,  from  food 
containing,  latent,  the  original  force  from  the  sun. 

We  stand  in  admiration  before  the  majestic  revolutions 
of  a  gigantic  water  wheel,  whose  force  is  distantly  conducted 
to  intricate  machinery,  constructed  to  minister  to  the  wants 


28         THE  EQUIVALENCE  OF  THE  FORCES. 

of  man.  Broad  belts  here  and  there  take  off  some  of  the 
force  for  widely  different  purpose.  The  antecedent  force  is 
gravitation,  which  causes  the  fall  of  the  water.  The  force 
behind  gravitation  was  that  which  lifted  the  water  to  its 
higher  level.  What  is  this  force  but  the  heat  of  the  sun 
which  has  raised  the  vapor  of  the  sea  to  the  clouds,  whence 
it  has  fallen  in  rain,  to  form  brooks  and  rivulets,  ever 
widening  streams,  the  force  of  whose  fall  (gravity)  may  be 
used  in  running  mills. 

The  swiftly  sailing  vessels  cleaving  the  breast  of  the 
waters  under  the  resistless  force  of  the  wind  is  no  less  indebted 
to  the  heat  of  the  sun,  the  unequal  distribution  of  which 
creates  the  currents  of  air  and  the  tides.  It  is  the  same 
force  of  the  wind,  produced  by  precisely  the  same  cause, 
which,  by  means  of  windmills,  lifts  whole  lakes  of  water 
from  inundated  lands. 

The  most  powerful,  and  the  most  widely  varied,  of  all 
our  machines,  the  steam  engine,  is  just  as  distinctly,  though 
not  so  directly,  driven  by  the  heat  of  the  sun.  For,  first 
of  all,  we  make  use  of  artificial  heat.  This  heat  is  the 
result  of  chemical  force,  the  union  of  oxygen  and  carbon, 
i.  e.,  coal,  which  contains  in  it,  latent,  the  original  heat  of 
the  sun.  This  chemical  force  produces  heat,  which  is  con- 
verted into  motion,  which  is,  in  turn,  again  converted  into 
heat  at  the  axles  of  the  wheels.  A  locomotive  has  there- 
fore been  likened  to  a  kind  of  distilling  apparatus,  which 
takes  heat  into  its  big  retort,  the  boiler,  converts  it  into 
motion  and  reconverts  the  motion  into  heat  at  the  axles  of 
the  wheels. 

The  Equivalence  of  the  Forces. 

What  especially  contributed  to  establish  the  doctrine  of 
the  conservation  of  force,  was  not  so  much  the  discovery  that 
one  force  could  be  converted  into  another,  but  that  one 


CONSERVATOIRE  DES  ARTS  ET  DES  METIERS.  29 

force,  or  one  form  of  force,  could  be  converted  into  another, 
quantity  for  quantity,  in  exact  equivalents.  Though  the 
constancy  of  the  forces  was  first  formally  announced  by 
Grove  before  the  London  Institution  in  1842,  it  did  not 
receive  general  acceptance  until  Mayer  and  Ilelmholtz,  of 
Germany,  and  more  especially  Joule,  cf  England,  had 
succeeded  in  establishing  the  equivalents  of  various  kinds 
of  force,  that  is,  the  amount  of  one  kind,  or  form  of  force, 
necessary  to  produce  a  certain  amount  of  another  kind  of 
force.  The  correlation,  or  convertibility  of  force,  is  thus 
based  upon  the  conclusion  that  the  whole  amount  of  force 
in  the  entire  universe  is  always  the  same.  It  may  change 
its  form  continually,  but  it  may  never  change  its  total 
sum.  Joule  first  discovered  the  equivalent  of  heat  to 
mechanical  force.  The  quantity  of  heat  sufficient  to  raise 
the  temperature  of  a  pound  of  water  one  degree  in  tempera- 
ture would,  when  properly  applied,  raise  a  pound  of  water 
772  feet  high.  One  degree  of  heat  is,  therefore,  equivalent 
to  the  mechanical  force  represented  in  an  elevation  of  772 
feet.  This  constant  relation  between  heat  and  mechanical 
force  has  been  confirmed  in  the  most  varied  manner  and 
the  law  thus  established  has  proven  of  the  highest  im- 
portance in  practical  adaptation  to  mechanics. 

As  every  form  of  steam  engine  is  an  illustration  of  the 
convertibility  of  heat  into  motion,  it  would  seem  needless 
to  cite  further  proof,  but  I  may  not  refrain  from  mention- 
ing the  curious  application  of  the  law  recorded  by  Liebig  in 
his  article  on  the  Connection  and  Equivalence  of  Forces  in 
the  case  of  the 

Conservatoire  des  Arts  ct  des  Metiers, 

in  Paris.  In  this  building,  which  was  formerly  a  convent, 
the  nave  of  the  church  was  converted  into  a  museum  for 
industrial  products,  machines  and  implements.     In  its  arch, 


30  CONVERSION   OF  MOTION  INTO  HEAT. 

traversing  its  whole  length,  appeared  a  crack,  which 
gradually  increased  to  the  width  of  several  inches  and 
permitted  the  passage  of  rain  and  snow.  There  were, 
doubtless,  not  wanting  individuals  at  this  time  who  looked 
upon  this  threatened  destruction  of  the  building  as  a  sign  of 
Divine  vengeance  for  its  desecration.  The  opening  could  have 
been  easily  closed  by  stone  and  lime,  but  the  further 
yielding  of  the  side  walls  would  not  have  been  thus 
prevented.  The  whole  building  was  on  the  point  of  being 
pulled  down  when  a  natural  philosopher  appeared  on  the 
scene  and  proposed  a  plan  which  finally  saved  the  building. 
A  number  of  strong  iron  rods  were  firmly  fixed  at  one  end 
to  a  side  wall  of  the  nave  and  after  passing  through  the 
opposite  wall  were  provided  on  the  outside  with  large  nuts 
which  were  screwed  up  tightly  to  the  wall.  The  nuts  were 
now  tight,  but  no  force  was  sufficient  to  move  the  walls 
a  line.  So  then  the  rods  were  heated  with  burning  straw, 
whereupon  they  extended  in  length.  The  nuts  were  thus 
removed  several  inches  from  the  wall  and  were  now  again 
screwed  up  further  on  to  the  thread  and  tight  to  the  wall.  The 
rods,  on  cooling,  contracted  with  enormous  force  and  made 
the  side  walls  approach.  By  repeating  this  operation  the 
crack  entirely  disappeared.  The  building,  with  its  retaining 
rods,  is  still  in  existence,  a  monument  to  the  triumph  of  a 
natural  philosopher  over  the  supposed  act  of  vengeance  of  an 
offended  Deity. 

Even  the  savages  knew  how  to  transform 

Motion  into  Heat 

by  the  friction  of  two  pieces  of  wood  or  by  striking  a  flint. 
A  skillful  blacksmith  can  render  an  iron  rod  red  hot  by 
hammering.  The  axles  of  our  carriages  have  to  be  greased 
to  lessen  the  heat  of  friction.  In  some  factories  where  a 
surplus  of  water-power  is  at  hand,  this  surplus  is  applied  to 


MOTION  FROM  ELECTRICITY.  31 

cause  a  strong  iron  plate  to  revolve  swiftly  upon  another, 
so  that  they  become  strongly  heated  by  the  friction.     The 
heat  so  obtained  warms  the  room  and  thus  is  secured  a  stove 
without  the  expense  of  fuel. 
An  example  of 

Motion  from  Electricity 

we  have  proclaimed  from  our  watch  towers  every  day  at 
noon,  or  on  the  occasion  of  every  fire.  Electricity  is  con- 
verted into  the  motion  of  the  hammer  which  falls  upon  the 
bell.  This  electricity  itself  is  the  product  of  chemical  action, 
that  between  zinc  and  acids  at  work  in  a  few  glass  cups. 
Almost  any  chemical  action,  as  the  oxidation  of  metals,  or 
the  burning  of  combustibles,  the  combination  of  oxygen 
and  hydrogen,  develops  electricity.  There  is  little  doubt 
that  the  time  will  soon  come  when  we  will  be  able  to  realise 
as  electricity  the  whole  of  the  chemical  force,  wrhich  is  active 
in  the  combustion  of  cheap  and  abundant  fuel,  such  as  coal 
and  wood  and  fat,  and  thus  "secure  a  mechanical  power  in 
every  respect  superior  to  its  applicability  to  the  steam 
engine." 

Even  now  we  convert 

Electricity  into  Light, 

whose  brilliance  over  that  from  every  other  artificial  source 
is  a  promise  of  the  power  yve  shall  one  day  possess  in  every 
field  of  mechanics.  Let  us  trace  up  the  transformations  of 
force  now  necessary  to  secure  a  powerful  electric  light.  First, 
light,  the  result  of  electricity,  produced  by  magnetism,  in 
turn  developed  by  the  mechanical  force  of  steam,  which 
force  is  a  transformed  chemical  force  evolved  in  the  com- 
bustion of  fuel,  containing  in  it,  latent,  the  original  light  of 
the  sun. 
In  every  case  we  finally  block  up  at  the  sun. 


32       THE  SUN   AS  THE  ULTIMATE  SOURCE  OF  FORCE. 

The  Sun  is  the   Ultimate  Source 

of  all  the  force  manifest  upon  the  earth.  With  the  excep- 
tion of  the  tidal  force,  partly  caused  by  the  attraction  of  the 
moon  and  which,  though  in  some  isolated  cases  it  is  utilised 
to  run  a  few  mills,  must,  nevertheless,  be  regarded  as  the 
earth's  greatest  foe,  because  it  is  insidiously  checking  up  the 
velocity  of  our  rotation,  with  the  inevitable  effect  of  finally 
plunging  us  into  the  sun,  with  this  exception,  all  terrestrial 
force  emanates  from  the  sun.  But  the  sun  is  so  vast,  its 
resources  are  so  enormous,  that  it  can  feed  our  whole  plane- 
tary system  and  still  irradiate  infinite  heat  into  interstellar 
space.  The  surface  of  the  sun  measures  115,000  millions  of 
square  miles  and  its  mass  is  350.000  times  greater  than  that 
of  the  earth.  The  amount  of  heat  aid  light  emanating 
from  the  sun  is  sufficient  to  account  for  all  the  force  of 
whatever  form,  manifest  upon  the  earth.  According  to  the 
pyrheliometric  measurements  of  Pouillet,  three  or  four 
•equivalents  of  heat  are  received  upon  every  square  foot  of 
the  earth  under  perpendicular  rays  of  the  sun.  The  amount 
received  daily  is  equivalent  to  that  engendered  in  the  con- 
sumption of  five  billions  tons  of  stone  coal,  which  is  again 
equal  to  sixty-six  billions  horse-power  every  hour.  If  the 
entire  quantity  of  solar  heat  received  in  a  year  were  uni- 
formly distributed  over  the  whole  surface  of  the  earth,  it 
would  suffice  to  melt  a  universal  layer  of  ice  one  hundred 
feet  thick  or  bring  from  the  freezing  to  the  boiling  point  an 
ocean  covering  the  earth  to  the  depth  of  fifteen  miles.  In 
every  second  of  time  the  sun  irradiates  into  space  as  much 
heat  as  would  result  from  the  combustion  of  eleven  thousand 
mx  hundred  billions  of  tons  of  stone  coal.  We  are  told  as 
an  easily  remembered  relation,  that  each  portion  of  the  sun's 
8U  rfacc,  as  large  as  our  earth,  emits  as  much  heat,  per  second, 
as  would  result  from  the  combustion  of  a  billion  tons  of  coal, 


ORIGIN  OF  THE  FORCES  ITSt  THE  SUN.  33 

whence  it  is  calculated  that  if  its  whole  mass  consisted  of 
coal  and  could  burn  right  out  to  the  last  ton,  maintaining 
till  then  the  present  rate  of  emission,  the  supply  would  last 
five  thousand  years.  The  small  pencil  of  rays  which  the 
earth  intercepts  at  a  distance  of  ninety-three  millions  of 
miles  is  only  the  one-twenty-three-hundred-millionth  part 
of  all  the  heat  irradiated  from  the  sun.  This  heat  at  the 
surface  of  the  sun  is  so  intense  as  to  volatilise  iron  and  other 
metals,  which  we  are  unable  by  any  known  method  of 
application  to  reduce  to  a  gaseous  state  upon  the  earth. 
The  enormous  quantity  and  intensity  of  heat  from  the  sun 
can  only  be  fully  comprehended  by  some  familiar  illustra- 
tion of  its  magnitude.  As  Helmholtz  has  put  it :  "Its  diame- 
ter is  so  great  that  if  you  suppose  the  earth  to  be  put  into 
the  centre  of  the  sun,  the  sun  itself  being  like  a  hollow 
sphere,  and  the  moon  going  about  the  earth  at  its  distance 
from  it  of  238,000  miles,  there  would  still  be  a  space  of 
more  than  200,000  miles  around  the  orbit  of  the  moon,  lying 
all  interior  to  the  surface  of  the  sun."  The  heat  and  light 
from  such  a  vast  source  of  power  are  thus  infinitely  more 
than  sufficient  to  account  for  every  form  of  force  upon 
earth  without  the  necessity  of  any  local  genesis. 

But  unde^  the  doctrine  of  the  conservation  of  force  we 
may  not  stop  at  the  sun.     What  then  is  the 

Source  and  Origin  of  the  Forces  in  the  Sun? 

The  original  signification  of  physiology,  a  description  of 
nature,  permits  us,  without  too  great  migration  from  our 
proper  studies,  to  consider,  for  a  moment,  the  workings  of 
nature  in  its  grandest  fields,  in  the  construction  and  move- 
ments of  the  heavenly  bodies.  I  avail  myself  here,  in  the 
main,  of  the  clear  and  concise  description  of  Helmholtz,  in 
his  paper  on  the  Interaction  of   the  Natural  Forces,  taking 


34  COMMENCEMENT  OF  THE  PLANETARY  SYSTEM. 

the  liberty,  simply,  of  condensation  and  omission  to  bring 
the  subject  within  the  limits  of  our  time. 

A  number  of  singular  peculiarities  in  the  structure  of  our 
planetary  system  indicates  that  it  was  once  a  connected  mass 
with  a  uniform  motion  of  rotation.  Without  such  an 
assumption,  it  is  impossible  to  explain  why  all  the  planets 
move  in  the  same  direction  around  the  sun,  why  they  all 
rotate  in  the  same  direction  around  their  axes,  why  the 
planes  of  their  orbits  and  those  of  their  satellites  and  rings 
all  nearly  coincide,  why  all  their  orbits  differ  but  little  from 
circles,  and  much  besides.  From  these  remaining  indica- 
tions of  a  former  state,  astronomers  have  shaped  an  hypo- 
thesis, regarding  the  formation  of  our  planetary  system, 
which  althougn  from  the  nature  of  the  case  it  must  ever 
remain  an  hypothesis,  still  in  its  special  traits  is  so  well 
supported  by  analogy,  that  it  certainly  deserves  our  atten- 
tion. No  other  hypothesis  has  ever  so  well  explained  the 
facts.  It  was  Kant,  first,  who,  penetrating  the  fundamental 
ideas  of  Newton,  seized  the  theory  that  the  same  attractive 
force  of  all  ponderable  matter,  which  now  supports  the 
motion  of  the  planets,  must  also,  in  ancient  times,  have 
been  able  to  form  from  matter  loosely  scattered  in  space 
the  planetary  system.  Afterwards,  and  independent  of 
Kant,  Laplace,  the  great  astronomer,  laid  hold  of  the  same 
thought  and  gave  it  the  support  of  his  fame. 

The  commencement  of  our  planetary  system  was  thus  an 

Immense  Nebulous  3Iass, 

which  filled  the  portion  of  space  now  occupied  by  our 
system  far  beyond  the  limits  of  Neptune,  our  most  distant 
planet.  Even  now  we  see  similar  masses  in  the  distant 
regions  of  the  firmament,  as  patches  of  nebulse  and  nebulous 
stars ;  and  within  our  system,  comets,  the  zodiacal  light, 
the  corona  of  the   sun  during  a  total  eclipse,  exhibit  rem- 


COMMENCEMENT  OF  THE  PLANETARY  SYSTEM.  35 

nants  of  a  nebulous  substance,  which  is  so  thin  that  the 
light  of  the  stars  passes  through  it  undiminished  and  un- 
bent. If  we  calculate  the  density  of  the  mass  of  our  plane- 
tary system  at  the  time  when  it  was  a  nebulous  sphere, 
reaching  out  to  the  path  of  the  outmost  planet,  we  find  that 
it  would  require  several  cubit  miles  of  such  matter  to  weigh 
a  single  grain. 

The  general  attractive  force  of  all  matter  must,  however, 
impel  these  masses  to  approach  each  other  and  to  condense 
so  that  the  nebulous  sphere  became  incessantly  smaller,  by 
which,  according  to  mechanical  laws,  a  motion  of  rotation, 
originally  slow,  would  gradually  become  quicker  and  quicker. 
The  enormous  centrifugal  force  thus  developed,  acting  most 
energetically,  of  course,  upon  the  equator  of  the  nebulous 
sphere,  would  swing  off  masses  from  time  to  time,  which, 
separating  from  the  main  mass,  would  form  themselves  into 
single  planets,  or,  similar  to  the  great  original  sphere,  into 
planets  with  satellites  and  rings,  until  finally  the  principal 
mass  left  condensed  itself  into  the  sun.  When  the  nebu- 
lous chaos  first  separated  itself  from  other  fixed  star  masses, 
it  must  not  only  have  contained  all  kinds  of  matter  which 
was  to  constitute  the  future  planetary  system,  but  also,  in 
accordance  with  our  new  law,  the  whole  store  of  force  with 
which  we  have  since  become  acquainted.  Then,  too,  an 
immense  dower  of  force  was  bequeathed  in  the  entire  or 
partial  arrest  of  the  general  attraction  of  all  the  particles 
for  each  other.  When  through  condensation  of  the  masses, 
particles  came  into  collision  and  clung  to  each  other  the 
force  of  gravity  is  lost  to  reappear  as  heat. 

The  store  of  force  yet  possessed  by  our  system  is  also 
equivalent  to  immense  quantities  of  heat.  If  our  earth,  whirl- 
ing about  the  sun  at  the  rate  of  eighteen  miles  a  second,  and 
whirling  on  its  own  axis,  in  our  latitude,  at  the  rate  of  110 
feet  a  second,  were  to  be  suddenly  stopped  in  its  orbit,  a 


36  HEAT  FROM  PROCESSES  OF  CONTRACTION. 

calamity  not  to  he  feared  in  the  present  condition  of  things, 
by  such  a  shock  a  quantity  of  heat  would  be  generated 
equal  to  that  produced  by  the  combustion  of  fourteen  such 
earths  of  solid  coal,  that  is,  the  earth  would  be  heated  to 
11,200  degrees  centigrade,  in  other  words,  it  would  be 
instantaneously  fused  and  converted  into  vapor.  When  it 
then  fell  into  the  sun,  as  would  of  necessity  be  the  case,  the 
quantity  of  heat  developed  by  the  shock  would  be  just  400 
times  greater  still  (Helmholtz). 

Here,  now,  we  have  something  of  a  clue  to  the  mysterious 
origin  of  the  heat  of  the  sun.  From  time  to  time  a  similar 
process  is  repeated  upon  our  earth  in  the  fall  upon  it  of 
meteors  or  meteoric  stones  deflected  from  their  course  about 
the  sun.  It  has  been  calculated  that  a  velocity  of  3,000 
feet  a  second  would  raise  a  piece  of  meteoric  iron  1000°  C. 
in  temperature,  or,  in  other  words,  to  a  vivid  red  heat. 
Now  the  average  velocity  of  meteors  is  thirty  to  forty  times 
this  amount,  and  we  can  thus  understand  why  it  is  that 
meteors  often  burst  upon  striking  the  earth  with  a  violent 
explosion,  or  are  completely  fused  to  vapor,  by  the  resistance 
of  the  air,  before  reaching  it  at  all. 

But,  it  is  now  generally  admitted  by  physicists  and 
astronomers  that  the  solar  heat  has  had  its  origin,  in  the 
main,  almost  wholly  in  fact,  in 

Processes  of  Contraction; 

and  that  it  is  maintained  by  such  processes.  In  other  words, 
the  gravitation  of  the  sun's  mass  has  given  birth  to  all,  or 
very  nearly  all,  the  heat  which  the  sun  has  emitted  in  the 
pa.st  and  will  continue  to  emit  to  the  end  of  his  career  as  a 
sun.  As,  however,  the  heat  resulting  from  this  contraction 
corresponds  to  only  about  twenty  million  years  supply,  a 
period  far  short  of  the  known  age  of  the  earth,  the  theory 
has  been  proposed  that  an  immense  store  of  heat  was  already 


CONVERSION  OF  GRAVITATION  INTO  HEAT.  37 

present  in  the  original  nebular  mass.  The  hypothesis  most 
generally  accepted  by  astronomers  at  present  derives  this 
original  heat  from  the  collision  of  dark  bodies  circulating  in 
space.  But  we  are  now  being  carried  too  far  away  from 
our  special  studies  in  the  attempt  to  follow  up  the  transfor- 
mations of  matter  and  force  in  the  remotest  history  of  the 
universe.  It  is  sufficient  for  our  purpose  to  know  that  the 
immense  store  of  force  in  the  sun,  like  the  insignificant  store 
of  the  earth,  was  also  derived  from  some  antecedent  force  ; 
and  whether  this  force  was  the  result  of  meteoric  bombard- 
ment of  the  sun,  as  formerly  believed,  or  of  continuing  con- 
densation of  matter,  as  now  maintained,  are  questions  of  no 
essential  difference.     The  practical  result  is  the  conversion  of 

Gravitation  into  Heat. 

To  form  even  a  faint  conception  of  such  mighty  forces, 
we  are  in  constant  need  of  some  familiar  standard.  Such  a 
basis  for  estimation  is  given  by  Mayer,  in  his  work  on 
Celestial  Dynamics,  in  the  case  of  the 

Gigantic   Wooden  Channel, 

in  which  tall  trunks  of  trees  were  allowed  to  glide  down 
from  the  steep  and  lofty  sides  of  Mount  Pilatus  into  the 
plain  below.  This  channel,  which  was  built  about  forty 
years  ago  by  the  engineer  Rupp,  was  nine  miles  in  length 
and  was  so  nearly  perpendicular,  that  the  largest  trees  were 
shot  down  it,  from  the  top  to  the  bottom  of  the  mountain,  in 
about  two  minutes  and  a  half.  The  momentum  possessed 
by  the  trees  on  their  escaping  at  their  journey's  end  was 
sufficiently  great  to  bury  their  thicker  ends  in  the  ground 
twenty  to  twenty-five  feet.  To  prevent  the  wood  getting 
too  hot  and  bursting  into  flames,  streams  of  cold  water  had 
to  be  let  into  the  channel  in  various  parts  of  its  course. 
But  this  stupendous  mechanical  process  appears  infinitely 


38  THE  PERPETUITY  OF  MATTER  AjStD  FORCE. 

small  when  compared  with  the  cosmical  processes  on  the 
sun.  It  is  here  the  mass  of  the  sun  which  attracts 
and,  in  lieu  of  the  height  of  Mount  Pilatus,  we  have  distances 
of  thousands  upon  thousands  of  miles.  The  amount  of  heat 
that  would  be  generated  by  cosmical  falls,  is  at  least  nine 
million  times  as  great. 

The  Perpetuity  of  Matter  and  Force. 

Such  are  the  questions  that  engage  us  and  the  conclusions 
that  face  us  in  studying  the  operations  of  the  Law  of  the 
Conservation  of  Force.  "Presented  rightly  to  the  mind," 
I  cite  from  the  eloquent  peroration  of  Mr.  Tyndall, 
"the  discoveries  and  generalizations  of  modern  science  con- 
stitute a  poem  more  sublime  than  has  ever  yet  been 
addressed  to  the  intellect  and  imagination  of  man.  The 
natural  philosopher  of  to-day  may  dwell  amid  conceptions 
that  beggar  the  visions  of  Dante  and  Milton.  So  great  and 
grand  are  they,  that  in  the  contemplation  of  them,  a  certain 
force  of  character  is  requisite  to  preserve  us  from  bewilder- 
ment." All  the  energies  of  our  earth,  mighty  as  they 
seem  to  be,  are  derived  from  the  small  pencil  of  rays  it 
receives  from  the  sun.  Of  this  store,  which  represents  but 
the  one-twenty-three-hundred-millionth  part  of  all  the  heat 
irradiated  from  the  sun,  but  a  small  fraction  is  really  stored 
up  in  latent  force.  And  in  all  the  lapse  of  human  history, 
at  least,  there  has  been  no  diminution  in  the  efflux  of  solar 
force.  "Measured  by  our  largest  terrestrial  standards  such  a 
reservoir  is  infinite ;  but  it  is  our  privilege  to  rise  above 
these  standards  and  to  regard  the  sun  himself  as  a  speck  in 
infinite  extension — a  mere  drop  in  the  universal  sea."  We 
pass  out  to  regions  in  space  where  all  our  planets  are  in- 
visible and  the  sun  himself  is  reduced  to  a  point  of  light. 
We  may  pass  again,  beyond  and  beyond,  to  points  where  the 
places  of  each  successive  survey  disappear  in  the  limitless 


PHYSIOLOGICAL   FORCE.  39 

regions  of  space,  boundless,  because  we  no  sooner  assign  a 
boundary  than  we  must  ask,  what  bounds  the  boundary. 
Everywhere  and  forever  is  the  same  force  and  matter  in  the 
midst  of  incessant  change.  Creation,  annihilation  still  re- 
main impossible  and  unknown.  Nebulae  may  condense  into 
systems  and  suns,  collisions  of  suns  may  reproduce  nebula?, 
our  earth,  our  whole  system,  nay,  our  visible  firmament 
might,  in  the  figurative  language  of  the  Orient,  be  indeed 
rolled  up  like  a  scroll  and  wafted  to  distant  regions  of  space, 
but  the  matter  and  the  force  must  forever  remain  the  same  ; 
secula  scculorum,  the  same. 

Physiological  Force. 

When  a  weight  is  lifted  by  the  hand  it  seems  a  long  way 
off  to  go  to  the  sun  for  the  muscular  force  necessary  to 
effect  it.  Yet  the  fact  is  capable  of  direct  proof.  All 
muscular  force,  all  force  of  whatever  character  in  the  body, 
is  directly  liberated  from  the  food.  We  have  already  seen 
how  the  light  and  heat  of  the  sun  become  locked  up  in  the 
plant  and  all  animal  life  is  directly  or  indirectly  dependent 
upon  the  life  of  plants.  Either  the  animal  feeds  upon  vegeta- 
bles exclusively,  as  in  the  case  of  the  herbivon,  or  it  feeds 
upon  the  flesh  of  these  animals  and  thus  indirectly  upon 
the  plant.  "The  carbonic  acid  of  the  air  which  is 
decomposed  by  the  plant,  is  decomposed  solely  and 
exclusively  at  the  expense  of  the  light  of  the  sun. 
Without  the  sun  the  reduction  can  not  take  place 
and  an  amount  of  sunlight  is  consumed  exactly  equivalent 
to  the  molecular  work  accomplished."  The  so-called  chemi- 
cal rays  of  sunlight  (blue  and  violet)  have  a  higher  affinity 
in  the  green  leaves  of  plants  for  the  carbon  of  the  carbonic 
acid  gas  than  has  oxygen.  The  carbonic  acid  gas  is  thus 
decomposed,  the  oxygen  is  set  free  and  the  carbon  and  the 
chemical  rays  of  the  sun,  which  thus  disappear  completely, 


40  PHYSIOLOGICAL  FORCE. 

are  locked  up  in  the  plant.  If  the  solar  rays  fall  upon  a 
surface  of  sand,  the  sand  is  heated,  but  the  heat  is  later 
irradiated  into  the  air,  but  if  these  rays  fall  upon  a  forest, 
some  of  it  is  retained  or  invested  in  the  structure  of  the 
trees.  "A  bundle  of  cotton  ignited  bursts  into  flames  and 
yields  a  definite  amount  of  heat ;  precisely  that  amount  of 
heat  was  abstracted  from  the  sun  in  order  to  form  that  bit 
of  cotton.  This  is  a  representative  case.  Every  tree,  every 
plant,  every  flower,  flourishes  and  blooms  by  the  grace  and  the 
bounty  of  the  sun"  (Tyndall). 

In  the  bodies  of  animals,  vegetables  are  burnt  up  just  as 
coal  is  burnt  up  in  the  furnace  of  the  engine  and  thus  is 
liberated  the  force  in  either  case.  So  much  fuel,  so  much 
force,  in  the  case  of  the  engine;  so  much  food,  so  much 
force,  in  the  case  of  the  animal  body.  The  plant  is  like  the 
clock  wound  up  but  not  running.  In  the  animal,  the  pendu- 
lum is  swung,  the  wheels  are  started  and  the  latent  force  is 
set  free.  The  clock  runs  down.  And  as  surely  as  the  force 
which  moves  the  clock's  hands  is  derived  from  the  arm 
which  winds  the  clock,  so  surely  is  the  force  of  the  muscle 
derived  from  the  sun. 

The  great  mass  of  organised  matter  in  both  plants  and 
animals  consists  (aside  from  water)  of  carbon  compounds ; 
carbon  united  with  oxygen,  hydrogen  and  nitrogen.  These 
compounds  are  built  up  in  plants  from  inorganic  matters 
in  the  earth  and  air.  The  carbon  is  chiefly  derived  from 
the  carbonic  acid  gas  in  the  air.  The  vast  magazines  of 
carbon  stored  away  in  our  inexhaustible  mines  of  coal,  ex- 
tending from  the  tropics  to  the  poles,  were  abstracted  from 
an  ancient  atmospheric  ocean  far  richer  in  this  gas  than  the 
air  about  us  now.  The  remaining  ingredients,  oxygen, 
hydrogen  and  nitrogen,  are  derived  from  water  and  air, 
and  the  ammonia  and  nitrates  constantly  present  in  each. 
Compounds  of  these  simple  bodies  are  constructed  in  the 


EXCRETIONS,   THE  PRODUCTS  OF  COMBUSTION.  41 

protoplasm  of  nature  in  the  vsame  manner  as  in  the  labora- 
tory of  art.  In  fact,  complex  organic  substances  have  been 
already  thus  artificially  compounded.  Wohler  first,  in  1828, 
made  urea  (CH4  No  O)  from  the  cyanate  of  ammonia  and 
a  number  of  organic  compounds,  allantoin,  for  instance, 
and  various  organic  acids  have  been  since  artificially 
constructed. 


Excretions,  the  Products  of  Combustion* 

The  essential  difference  between  organic  and  inorganic 
compounds  lies  in  the  fact  that  the  inorganic  compounds 
are  products  of  oxidation  (combustion).  They  have  been 
already  oxidised,  these  ashes  of  nature,  and  admit  of  no 
further  combustion.  Organic  compounds,  on  the  other 
hand,  containing  little  or  no  oxygen,  are  still  highly 
oxidisable  (combustible):  The  phenomena  of  life  ;  that  is, 
the  liberation  of  the  latent  forces  stored  up  in  these  com- 
pounds ;  depend  upon  the  oxidation  of  these  compounds. 
"We  have  as  the  result  of  life  precisely  the  same  oxidation 
products  (excretions)  from  these  compounds  as  after  their 
more  direct  combustion.  When  an  animal  or  a  vegetable 
body  is  burned  (oxidised),  the  mass  of  it  is  resolved  into 
the  gases  of  combustion.  The  carbon  unites  with  oxygen 
to  become  carbonic  acid  gas  (CO>),  the  hydrogen  unites 
with  oxygen  to  form  water  (H20),  or  with  nitrogen  to  form 
ammonia  (NH3),  while  the  phosphorus  and  sulphur  (when 
present)  remain  with  other  inorganic  matter  in  the  ash. 
Examination  of  the  ash  reveals  carbon  (not  escaped  in  gas), 
chlorine,  potassium,  sodium,  calcium,  magnesium,  iron,  etc. ; 
the  same  elements  and  principles  discovered  in  the  various 
excretions  of  the  living  body. 

When  the  Duke  would  excite  in  the  mind  of  Claudio 


42  EXCRETIONS,   TIIE  PRODUCTS  OF  COMBUSTION". 

(Measure  for  Measure)  a  contempt  of  life,  lie  advises  him : — 

*  *        *        "Reason  thus  with  life: — 

*  *  *  a  breath  thou  art, 

(Servile  to  all  the  skiey  influences), 
***** 

For  thou  exist' st  on  many  a  thousand  grains 
That  issue  out  of  dust." 

The  plant-cell,  then,  absorbs  from  the  earth  and  air  these 
inorganic,  oxidised  compounds,  and  under  the  light  and 
heat  of  the  sun  liberates  the  oxygen  and  fixes  the  now 
deoxidised  compounds  in  their  substance;  whereas  the 
animal  cell  absorbs  (ingests)  the  deoxidised  compounds 
and  the  oxygen  with  which  it  burns  (oxidises)  them,  and 
thus  again  reduces  them  to  gases  and  salts  for  reabsorption 
by  the  plants.  That  is,  the  earth  and  air  feed  the  plants, 
the  plants  feed  the  animals,  the  animals  feed  the  earth  and 
air.  This  is  the  great  circle  of  nutrition  in  nature.  The 
carbon  of  the  carbonic  acid  gas  in  the  air  becomes  the  carbon 
of  cellulose,  starch,  sugar,  fat,  etc.,  of  the  plant,  which, 
in  turn,  furnishes  carbon  for  the  albumen  in  the  blood, 
muscle,  brain,  etc.,  of  the  animal,  by  which  it  is  again 
delivered  over  as  carbonic  acid  to  the  air,  whence  it  was 
derived. 

The  plant-cell  fixes  in  its  body  as  latent  force  the  light 
and  heat  of  the  sun,  that  the  animal  cell  may  set  it  free  in 
other  forms,  as  in  heat,  electricity,  mechanical  work,  nerve- 
force,  etc.  But  that  the  animal  cell  may  possess  this  power, 
it  must  make  constant  consumption  of  oxygen  gas.  In 
the  body  of  man,  where  the  liberation  of  forces  meets 
itshighest  expression,  the  consumption  of  oxygen  is  immense. 
A  man  of  average  weight  inhales,  by  various  avenues, 
700-1000  grammes  per  day,  that  is  500-700  pounds  of 
oxygen  a  year.  And  as  the  great  bulk  of  his  body  is  composed 
of  material  already  thoroughly  oxidised    (two-thirds    to 


THE  FORCE  VALUE  OF  FOODS.  43 

three-fourths  of  it  is  water),  it  may  be  readily  seen  that  all 
the  organic  matter  of  the  body  would  be  soon  resolved  into 
gases  and  ash,  were  it  not  for  the  new  matter  constantly 
furnished  by  the  food.  The  new  matter  thus  furnished  so 
nicely  balances  the  loss  by  oxidation  that  the  body,  though 
in  incessant  change,  may  lose  nothing  of  its  weight  in  years. 
And  that  the  atmosphere  may  also  remain  the  same  under 
the  constant  abstraction  of  oxygen  by  animal  cells,  this 
gas  must  be  as  perpetually  furnished  by  the  plants.  Thus, 
that  the  700-1000  grammes  of  oxygen,  appropriated  by 
each  human  being  in  a  day,  to  say  nothing  of  other  animals, 
may  be  restored  to  the  air,  the  plant  must  decompose 
enough  water  and  carbonic  acid  gas  to  make  33-40  lbs.  of 
starch,  cellulose,  etc.,  in  the  same  period  of  time. 

Animal  Bodies  as  Machines. 

Our  bodies  come,  therefore,  to  be  regarded  as  machines 
for  the  exhibition  of  various  forms  of  force.  As  the  steam 
engine  liberates  in  other  forms  the  forces  stored  up  in  the 
fuel,  the  body  sets  free  in  the  phenomena  of  life,  the  forces 
stored  up  in  the  food.  We  are,  however,  unable  as  yet  to 
construct  a  machine  that  may  liberate  force  as  perfectly  as 
the  human  body.  Helmholtz  has  shown  that  the  best  steam 
engine  can  convert  into  motion  only  one-tenth  of  the  force 
of  its  fuel,  the  remaining  nine-tenths  escaping  as  heat ; 
whereas  the  body  of  man  may  transform  into  mechanical 
work  as  much  as  one-fifth  of  the  force  of  his  food,  the  re- 
maining four-fifths  escaping  with  the  unoxidised,  that  is, 
the  unburnt,  compounds  in  the  various  excretions. 

The  Force   Value  of  Foods. 

The  force  of  the  body  being  thus  directly  derived  from 
the  food,  and  the  amount  of  heat  being  known  which  the 
combustion  of  any  article  of  food  outside   the  body   will 


44  COST   OF  FUEL   AND    FOOD. 

produce,  it  is  easy  to  compute  the  force  value  of  the  different 
kinds  of  food.  Frankland  has  thus  tabulated  the  force 
value  of  foods  and  has  shown,  as  might  have  been  antici- 
pated, that  the  most  highly  combustible  articles  of  food,  the 
fats,  stand  at  the  head  of  the  list  in  the  amount  of  force  that 
may  be  liberated  in  their  digestion.  Thus,  half  a  pound  of 
fat  furnishes  the  same  amount  of  force  as  one  and  one-third 
pounds  of  flour,  one  and  one-half  pounds  of  sugar,  three 
and  one-half  pounds  of  lean  beef  and  live  pounds  of  potatoes. 
The  laboring  man  gets  from  his  slice  of  breakfast  bacon 
more  work  than  the  retired  merchant,  professional  man  or 
epicure  can  obtain  from  a  table  overloaded  with  other  things. 
The  appetite  comes  thus  to  be  recognised  as  a  measure  of 
the  capacity  for  work.  A  farmer  when  asked  "how  he  could 
afford  to  pay  his  laborers  so  well,"  replied,  that  "he  could 
not  afford  to  pay  them  less,  as  less  wages  meant  less  food 
and  less  work."  Another  sat  at  the  table  with  his  men  and 
wThen  he  found  one  of  them  taking  less  food  he  turned  him 
off,  as  he  at  once  knew  that  that  individual  was  shirking  his 
work.  Longet  relates  that  in  1841,  some  English  and  French 
laborers  were  engaged  in  the  construction  of  a  railroad  from 
Paris  to  Rouen.  It  was  soon  discovered  that  the  French 
laborers  could  accomplish  only  about  two-thirds  as  much 
work  as  the  English.  It  was  suspected  that  this  deficiency 
of  force  was  due  to  the  deficiency  of  food.  The  French 
laborers  were  thereupon  supplied  with  an  equal  amount  of 
food  and  soon  were  able  to  accomplish  an  equal  amount  of 
work.  "The  muscular  strength,  the  intelligence  and  com- 
mercial industry  of  a  people  depend  upon  the  proper  use 
and  right  distribution  of  its  food/' 

Cost  of  Fuel  and  Food. 

But  if  force  is  more  fully  set  free  by  the  human  body  than  by 
a  machine,  the  question  becomes  pertinent:  why  not  employ 


COST  OF   FUEL  AND  FOOD  45 

human  beings  for  mechanical  work  rather  than  machinery. 
The  answer  is  very  easy ;  because  of  the  cost  of  food  in  com- 
parison with  fuel.  A  steam  engine  will  work  all  day  at  a 
cost  for  its  fuel  of  twenty  cents ;  the  food  of  two  horses,  the 
equivalent  of  the  machine,  costs  $2.00;  and  the  food  of 
twenty-four  men,  required  to  perform  the  same  work,  costs 
$10.00.  Hence,  as  Donders  has  shown,  the  animal  body  can 
never  successfully  compete  with  the  steam  engine,  and  "the 
worst  use  to  make  of  a  man  is  to  employ  him  exclusively  in 
mechanical  work,  a  statement  which  harmonizes  with  the 
increased  introduction  of  machinery  in  our  advancing 
civilization." 

If  we  should  allow  any  humanitarian  influence  a  place 
at  all  in  this  consideration,  we  should  have  to  remember  also 
that  if  we  divert  all  the  force  in  the  body  to  mechanical 
work,  there  is  none  left  for  mental  work.  The  force  of  the 
body  is  of  course  pretty  much  a  fixed  quantity,  just  as  it  is 
for  a  machine,  depending  largely  upon  its  original  construc- 
tion, as  determined  by  heredity.  We  cannot  use  all  the 
power  of  a  machine  for  a  special  purpose,  say  to  saw  a  log, 
and  have  enough  left  to  turn  a  mill-stone.  So  with  very 
few  exceptions  hard  muscular  workers  achieve  no  eminence 
in  intellectual  life.  Stallions  whose  force  is  to  be  used  in 
reproduction  are  kept  idle  in  the  stalls. 

The  body  of  man  is  built  up  of  cells  (protoplasm),  which 
are,  in  turn,  composed  of  atoms  or  molecules,  whose  arrange- 
ment (transmitted  by  heredity  and  modified  by  external 
conditions)  determines  the  special  action  or  use.  Or,  as 
Goethe  has  put  it :  "Nicht  allein  das  angeborene,  auch  das 
Enoorbene  ist  der  Mensch."  (Man  is  not  alone  what  he 
inherits ;  he  is  also  what  he  acquires.)  The  action  of 
protoplasm,  though  sometimes  apparently,  is  never  really 
spontaneous.  The  cells  are  called  into  action  by  stimu- 
lus, which,    so    far    as     we    can     trace     it,   always    pro- 


46  PHYSIOLOGICAL,    A   PHYSICAL  FORCE. 

ceeds  from  without.  The  various  phenomena  of  life 
are  principally  manifestations  of  reflex  action.  In 
simple  bodies  (individual  masses  of  protoplasm)  the  out- 
side stimulus  is  conveyed  from  atom  to  atom,  like  chemical 
force  in  gunpowder,  from  grain  to  grain.  In  complex 
bodies  the  stimulus  is  carried  along  definite  trains  (nerve- 
strands)  to  special  destinations.  If  a  muscle  contract,  it 
contracts  in  obedience  to  stimulus  carried  to  it  by  a  motor 
nerve.  The  stimulus  conveyed  along  the  nerve  has  its 
development  in  a  nerve-center  (ganglion).  The  stimulus 
experienced  in  the  nerve-center  is  in  turn  derived  from 
a  sensitive  nerve.  The  sensitive  nerve  transmits  an  im- 
pression received  upon  a  sensory  surface  (skin,  mucous 
membrane,  gland,  etc.).  Even  the  most  complex  mani- 
festations of  the  brain  fall  under  the  same  category.  So- 
called  voluntary  movements  are  only  the  final  responses  to 
impressions  made  upon  the  special  senses  at  the  time  or  in 
the  past  (memory).  The  highest  expressions  of  the  intellect 
of  man  may  be  resolved  into  the  more  perfect  transmutations 
of  outside  forces  by  machinery  made  more  perfect  by  original 
construction  (heredity),  or  made  more  perfect  by  labor, 
(education). 
Thus  : 

Physiological  is  Correlative  with  Physical  Force, 

or,  more  literally  expressed,  is  identical  with  physical 
force,  and,  the  matter  of  our  bodies  being  the  same,  and  the 
forces  which  operate  upon  it  being  the  same,  as  in  the  inorganic 
world,  the  exhibition  of  life  is  no  more  due  to  an  innate 
principle,  a  separate  essence,  a  quid  intus,  a  something 
within,  than  is  the  registry  of  time  in  a  clock. 


THE  ORIGIN  AND  EVOLUTION  OF  LIFE.  47 


LECTURE   III. 
THE  ORIGIN  AND  EVOLUTION  OF  LIFE. 

C  O  NTENTS. 

Definitions  of  Physiology — Ancient  Definitions  of  Life — Modern  Defi- 
nitions of  Life — Difference  between  Organic  and  Inorganic  Matter 
— The  Property  of  Assimilation — Period  of  Development  of  Life — 
The  Theory  of  Evolution — Palaeontology — The  Cataclysms  of  Cuvier 
— The  Operation  of  Existing  Causes — The  Age  of  the  Earth — The 
Evolution  of  Fossil  Forms. 

Physiology  (ow^f,  Aoyog),  in  our  day,  has  a  meaning  very 
different  from  the  old  conception  of  the  term.  It  is  no 
longer  a  "description  of  nature"  in  general,  according  to  its 
literal  origin  and  primitive  significance.  The  vast  collection 
of  facts  in  natural  science,  accumulated  since  physiology 
first  was  taught,  has  been  classified  in  appropriate  lists,  and 
relegated  to  special  and  separate  departments.  The  range 
of  physiology  in  ancient  times  becomes  apparent  from  the 
titles  of  the  works  of  the  oldest  authors.  Thus,  Aristotle 
wrote  a  work  entitled  Historic!,  Partes,  Incessus,  Motus, 
Generatioque  Animallum;  atque  Plantarum  natures  brevis 
descriptio.  Aristotle  was  the  first  to  use  the  term  61  <j>vcno2.oyoi, 
designating  as  such,  Thales,  Anaximenes,  Heraclitus,  Dio- 
genes, Empedocles  and  Anaxagoras,  philosophers  who  were 
engaged  in  the  study  of  the  nature  of  things,  their  causes 
and  commencements.  Fernel  first  (1538)  limited  the  term 
to  the  nature  of  man  in  health.  Boerhaave  and  Haller  used 
it  in  the  sense  of  the  use  or  actions  of  the  various  parts  of 
the  body.  Synonims  of  Physiology  were  the  Philosophy  of 
Living  Bodies,  Dynamology,  Organonomia,  Zoonomia, 
Biology.  Johannes  Muller  (1833),  "who  dealt  the  death 
blow  to  vitalism"  in  physiology,  called  it  "The  Physics  of 


48  ANCIENT  DEFINITIONS  OF  LIFE. 

Organisms,"  basing  it  solely  upon  Anatomy,  Chemistry  and 
Physics. 

Physiology,  in  its  modern  sense,  is  limited  to  the  phe- 
nomena observed  only  in  living  things,  and  though  really 
only  more  closely  allied  with  subjects  not  especially  endowed 
with  life,  it  has  gradually  become  disencumbered  from 
necessary  consideration  of  them.  Physiology  is,  in  short, 
biology,  the  science  of  life. 

What,  then,  is  Life? 

A  satisfactory  definition  of  life  in  a  few  words  was  a  want 
experienced  long  before  physiology  was  studied  as  a  separate 
branch  of  knowledge.  With  the  ancients  this  question  was 
easily  answered.  Life  to  them  was  a  miracle,  a  supernatural 
creation.  "Humanity  in  its  infancy,  like  the  infant  still 
in  humanity,  was  satisfied  with  a  word  it  could  not  compre- 
hend." Every  inexplicable  event,  from  an  eclipse  to  an 
epidemic  disease,  was  accepted  as  a  miracle,  and  further 
inquiry  was  prevented,  if  not  punished,  indeed,  as  a  presump- 
tion upon  the  prerogatives  of  the  gods. 

Ancient  Definitions  of  Life. 

Or,  later,  definitions  of  life  were  evolved  from  the  revel- 
ries of  metaphysics.  Life,  said  Thales,  of  Miletus,  emanates 
from  water  with  every  other  earthly  thing.  According  to 
Pythagoras,  the  principle  of  life  is  heat.  Alcmeon  thought 
that  the  principle  of  life  was  in  the  blood,  but  the  soul,  a 
distinct  principle,  was  seated  in  the  brain.  The  chief  ingre- 
dient in  the  manufacture  of  life  for  Empedocles  was  fire, 
though  water,  air  and  earth,  all  the  elements,  entered  into 
its  composition.  It  was  with  fire  stolen  from  heaven  that 
Pygmalion  infused  the  breath  of  life  into  his  marble  statue. 
Hippocrates,  most  wise  of  all,  refrained  from  any  definition 
of  life,  and  counseled  the  study,  not  of  its  causes,  but  of  its 


ANCIENT   DEFINITIONS   OF   LIFE.  49 

manifestations.  Plato,  the  great  spiritualist,  maintained 
that  the  rational  soul,  an  immaterial  essence,  was  located 
in  the  brain,  the  irrational,  likewise  an  essence,  in  the  abdo- 
men. The  body  is  only  the  theater  in  which  the  soul  lives, 
and  thinks  and  acts.  Aristotle  subdivided  the  soul  to  such 
extent  as  to  localise  its  parts  in  every  organ,  whose  functions 
the  special  parts  direct.  The  still  popular  "animation"  of 
the  heart,  stomach,  bowels,  liver,  spleen  and  kidneys  is  the 
relic  of  these  views.  In  the  reaction  which  naturally 
followed  this  exaltation  of  the  soul,  Epicurus,  like  Demo- 
critus  before  him,  renounced  the  soul  entirely  with  every 
form  of  immateriality.  The  body  is  only  an  accidental 
collocation  of  atoms,  whose  aggregation  and  arrangement 
explains  the  different  functions.  Galen  with  his  pneuma 
again  restored  the  soul  as  the  principle  of  life.  It  was 
developed  in  the  ventricles  of  the  brain,  and  lodged  in  the" 
arteries,  the  air  or  pneuma  carriers,  whence  they  have  their 
name.  But  with  Galen  came  again  the  reinstatement  of 
observation,  as  recommended  by  Hippocrates,  and  the  first 
establishment  of  experiment.  Galen  is  thus  justly  looked 
upon  as  the  father  and  the  founder  of  scientific  physiology. 
Unfortunately,  his  example  had  no  followers.  "Fireside  and 
writing-desk  theories" — easier  paths  to  notoriety — soon  sup- 
planted bed-side  observations  and  experimental  studies,  one' 
after  another  triumphing  in  turn,  until  everything  was  lost 
in  the  succeeding  darkness  of  the  middle  ages.  "The  field 
of  physiology  illuminated  for  a  moment  by  the  genius  of 
Galen  was  then  enshrouded  in  twelve  centuries  of  gloom." 

After  the  long  night  of  ignorance  and  superstition  broke 
the  dawn  of  the  day  which  is  still  upon  us  in  glimmers  of 
light  from  the  natural  sciences.  From  the  still  smouldering 
embers  of  alchemy  and  astrology — as  Christianity-  upon  the 
altars  of  the  unknown  gods — -were  fanned  the  flames  of  modern 
chemistry,  physics,  and  the.  other  natural  sciences,  under 

5 


50  MODERN   DEFINITIONS   OF  LIFE. 

the  light  of  which  were  read  new  interpretations  of  the  prin- 
ciple of  life.  Paracelsus,  Van  Helmont  and  Sylvius,  could 
see  in  its  most  complicated  phenomena  nothing  but  effects 
of  combinations  in  chemistry.  Descartes  introduced  the 
new  science  of  mechanics.  "The  body  had  been  an  alembic ; 
now  it  was  a  machine.  The  principles  of  gravity,  mechanics 
and  hydrostatics  served  to  explain  the  phenomena  of  the 
senses,  the  movements  of  organs,  the  exercise  of  all  the 
functions,  and  even  the  acts  of  intelligence"  (Longet). 

Again,  there  was  reaction  toward  a  vital  as  distinct  from 
physical  force.  Haller,  who  was  second  only  to  Harvey, 
for  having  revived  anew  the  long  neglected  studies  by  direct 
observation  and  experiment  in  lieu  of  surmise  and  specula- 
tion, discovered  the  inherent  "irritability"  in  various  tissues, 
a  property  innate  to  the  tissue  itself,  and  characteristic  of 
living  matter. 

Modern  Definitions  of  Life. 

The  definition  of  life  in  our  own  day  has  been  mostly  a 
play  upon  words.  Bichat  says  "life  is  the  sum  total  of  the 
functions  which  resist  death."  Lawrence  declares  it  to  be 
"an  assemblage  of  all  the  functions  or  purposes  of  organised 
bodies,  and  the  general  result  of  their  exercise."  Lewes 
defines  life  as  "a  series  of  definite  and  successive  changes 
without  destruction  of  identity."  Duges  calls  it  "the  special 
activity  of  organized  bodies,"  Beclard,  "organisation  in 
action,"  and  Spencer,  "the  coordination  of  action."  Truly,  it 
might  be  said  of  all  these  phrases,  they  are  only  idle  repe- 
titions of  "life  is  life." 

Thus,  to  define  physiology  as  the  science  of  life,  is  one 
thing;  but  to  define  life,  the  subject  of  which  it  treats, 
is  another.  One  might  almost  say  that  the  definition  of 
life  is  a  rock  surrounded  with  shipwrecked  attempts.  It 
is  no  answer  whatever  to   say    that    life    is  a  creation. 


ORGANIC  AND  INORGANIC   MATTER.  51 

Such  an  assertion  may  satisfy  the  wants  of  the  emotions, 
but  it  will  in  no  way  appease  the  demands  of  the  intellect, 
trained  by  cultivation  in  physical  science  to  entirely  ignore 
unnatural  explanations  for  natural  events.  Equally  empty 
and  evasive  in  the  pcriphrase  that  life  is  the  result  of  all  its 
phenomena. 

Difference  between  Organic  and  Inorganic  Matter. 

May  we  succeed  better,  perhaps,  with  the  understanding 
of  life  by  a  comparison  between  matter  endowed  with  it, 
and  that  which  is  not  ?  Automata  have  been  made  to 
simulate  every  visible  manifestation  of  life.  Vaucanson's 
duck  could  walk,  talk,  i.  e.,  utter  sounds  (Faber's  machine 
could  talk),  eat,  digest  food,  and  even  void  per  anum 
indigestible  residue.  Yet  this  automaton  was  wholly  built 
up  of  wheels  and  springs,  retorts  and  tubes,  mechanical 
and  chemical  devices,  a  cunning  contrivance  to  nearly 
realise  the  fanciful  conception  of  Frankenstein.  In  what 
respect  does  such  a  finished  piece  of  mechanism  differ  from 
an  organism,  a  really  living  thing  ? 

It  has  been  said  that  the  activity  of  an  organism  is  innate, 
while  that  of  a  mechanism  is  accidental.  An  animal  lives, 
moves,  and  has  its  being  of  itself,  while  a  machine,  steam- 
engine  or  watch  must  be  supplied  with  fuel  or  wound  up 
before  its  activity  is  shown. 

But  an  organism  is  no  more  capable  of  living  without 
food,  than  a  machine  of  running  without  fuel.  The  food 
is  fuel  in  a  literal  sense,  and  it  is  the  combustion  of  the  food 
in  the  body  of  man,  as  it  is  the  combustion  of  fuel  in  the 
furnace  of  the  engine,  that  develops  the  force  in  either 
case. 

Again,  it  has  been  said  that  activity  of  some  kind  or  other 
is  essential  to  the  organism,  but  unessential  to  the  mechanism ; 
that  is,  if  the  organism  ceases  to  act,  it  perishes  and  is  lost, 


52  THE  PROPERTY   OF   ASSIMILATION. 

whereas  an  engine  remains  an  engine,  or  a  watch  remains 
a  watch,  even  though  not  set  in  motion  for  years.  But  we 
know  many  organisms  that  have  ceased  to  show  any  signs 
of  life  for  years  and  yet  still  exist  as  such.  Small  wheel- 
like animals,  tardigrades,  rotifers,  etc.,  may  be  completely 
dried  up  and  kept  as  lifeless  particles  for  years,  to  be  re- 
stored with  every  manifestation  of  life,  swimming  as  actively 
as  before,  on  being  put  again  in  water.  Frogs  and  fishes, 
low  in  the  scale,  have  been  frozen  hard  into  inanimate  bodies 
and  again  thawed  into  life.  Seeds  from  the  tombs  of 
mummies  have  been  made  to  germinate  and  bear  fruit 
after  the  desiccation  of  a  thousand  years. 

Nor  can  the  much-vaunted  power  of  reproduction  be 
looked  upon  as  a  criterion  of  living  things.  The  power  of 
reproduction  is  present  only  at  a  certain  phase  of  life  in  all 
animals  and  plants,  and  yet  at  every  period  are  they  none 
the  less  alive.  Besides,  many  living  things  are  sterile 
throughout  life,  as  the  workers  among  bees,  the  soldiers  of 
ants,  hybrids  among  horses,  etc. 

Nor,  again,  may  it  even  be  maintained  that  every 
living  thing  is  descended  from  a  parent  like  itself;  for 
many  species  of  animals  and  plants  now  upon  the  earth 
differ  so  entirely  from  ancestral  forms  as  to  have  been  long 
regarded  as  entirely  different  species.  A  skilled  zoologist  is 
required  to  trace  the  resemblance  between  fossil  and  existent 
forms. 

The  Property  of  Assimilation. 

Nevertheless,  observes  Briicke,  who  has  so  clearly  estab- 
lished these  refutations  of  long  accepted  views,  we  do  possess 
a  difference,  which  enables  us  to  separate  living  from  lifeless 
matter.  Organisms  have  the  property,  with  which  no 
mechanism  of  any  kind  has  ever  been  endowed,  of  taking 
up  foreign  matter  and  transforming  it  into  their  own  sub- 


THE  PROPERTY   OF   ASSIMILATION.  53 

stance  ;  and  the  organism  grows  at  the  expense  of  the 
substance  thus  acquired.  This  is  the  property  of  assimila- 
tion. "It  pertains  to  every  organism,  so  long  as  it  is  an 
organism,  and  must  pertain  to  every  organism,  because 
upon  it  is  based  its  whole  organic  life."  But  if  we  contrast 
the  growth  of  an  organism  with  the  growth  of  inorganic 
matter  we  may  not  make  this  difference  so  distinct.  For, 
in  the  first  place,  we  observe  that  the  elements  which  go  to 
form  an  organism  are  not  different  from  those  that  constitute 
inorganic  matter.  The  carbon,  hydrogen,  oxygen  and 
nitrogen  of  living  matter  are  precisely  the  same  carbon, 
hydrogen,  etc.,  in  the  inorganic  world.  A  simple  monad, 
a  shapeless  mass  of  protoplasm,  scarcely  contains  as  many 
elements  as  a  piece  of  common  feldspar.  That  either 
should  increase  in  size,  it  must  be  placed  in  a  medium  con- 
taining matter  like  itself,  or  that  may  be  cjianged  into  matter 
like  itself.  In  the  slow  evaporation  of  the  solution  of  a  salt, 
the  formation  of  crystals  develops.  Each  crystal  particle 
grows  by  addition  to  its  surface.  In  the  growth  of  an 
organism  the  addition  is  effected  from  within.  So  far  as 
growth  is  concerned  the  essential  difference  between  the  two 
is  merely  one  of  density.  Organisms  are  of  soft  consistence, 
hence  are  penetrable  to  nutrient  matter.  Inorganic  matter, 
from  its  nature,  is  hard  and  dense,  impenetrable  from  with- 
out. Growth  may  only  take  place  on  its  surface,  but  it  is 
here,  as  in  the  organism,  always  at  the  expense  of  the  new 
material.  It  is  true  that  in  the  organism  the  new  material 
is  subjected  to  chemical  change,  a  new  arrangement  of  its 
atoms  resulting  from  its  absorption  and  assimilation,  but 
this  change  is  due  to  the  fact  that  carbon,  the  principal 
elementary  ingredient  of  organic  bodies,  has  such  multi- 
tudinous and  varied  relations  with  all  the  other  elements. 
In  other  words,  the  various  manifestations  of  life,  in  its 
simplest  forms  at  least,  admit  of   explanation  on  physical 


54  PERIOD  OF  DEVELOPMENT  OF  LIFE. 

grounds  alone  ;  and,  so  far  as  growth  and  reproduction  are 
concerned,  it  is  no  more  necessary  to  invoke  the  phantom  of 
a  mystic  vital  force  in  their  comprehension,  than  in  the 
explanation  of  the  form  or  formation  of  a  crystal  in  the 
inorganic  world. 

Whatever  theory  we  may  adopt  as  to  the  nature  of  life, 
there  is  no  longer  any  doubt  as  to  the 

Period  of  its  Development  upon  our  Earth, 

that  is,  it  is  positively  known  that  life  did  not  appear 
coeval  with  the  dissipation  of  the  chaotic  confusion  which 
marks  the  first  epoch  in  every  theory  of  creation.  Ages 
must  have  lapsed  before  the  necessary  conditions  of  life 
could  have  developed. 

Two  theories  prevail  at  present  in  the  civilized  world 
regarding  the  firs&,creation  of  life  ;  the  so-called  miraculous 
and  non-miraculous  theories.  These  theories  are  more 
euphemistically  designated  the  teleological  and  mechanical 
theories ;  teleological  {rzloc^  end  and  7.oyoq,  discourse)  because 
evincing  design,  according  to  human  conception  of  the  term ; 
and  mechanical  in  the  sense  of  being  explicable  by  the  action 
of  natural  laws  in  continuous  operation.  The  miraculous  is  the 
supernatural  theory  as  revealed  in  the  first  book  of  Genesis. 
Because  it  has  received  its  finest  exposition  in  our  day  at 
the  hands  of  the  great  English  poet,  Milton,  this  theory  is 
often  called  the  Miltonic  theory.  It  is  depicted  in  the 
Bible  with  the  solemn  cadence,  the  metaphor  and  poetic 
imagery,  the  "inspiration,"  characteristic  of  the  Orient.  In 
its  regular  sequence  of  chaos,  darkness,  absence  of  form  and 
life,  then  lir^ht,  water,  vegetation,  aquatic  life,  land  life, 
and,  last  of  all,  man,  it  is  in  perfect  harmony  with  the  natural 
theory  of  creation.  But,  in  its  disposition  of  the  earth  as 
the  center  of  the  universe,  and  of  man  as  the  center  of  all 
life,  it  is  directly  opposed  to  all  the  facts  of  astronomy, 


PERIOD  OF  DEVELOPMENT  OF  LIFE.  55 

geology  and  biology.  The  earth  we  know  to  be  but  an 
atom  in  the  illimitable  expanse  of  space  and  we  have 
reason  to  consider  man  but  as  an  accident  of  conditions 
upon  its  surface  prevailing  at  his  time. 

The  non-miraculous  is  the  natural  theory  of  creation. 
This  theory  in  the  first  place  repudiates  every  idea  of  crea- 
tion in  the  strict  sense  of  the  term.  Such  a  thing  as  the 
creation  of  a  new  substance  is  impossible  and  unknown. 
The  matter  of  which  our  earth  consists  has  existed  and  will 
exist  forever.  It  may  become  subject  to  as  many  changes 
in  future  ages  as  it  has  undergone  in  the  past;  it  may, 
ultimately,  even  lose  its  separate  existence  and  identity  by 
fusion  with  other  globe's  of  matter  and  return  to  a  former 
nebulous  state,  but  the  matter  of  its  present  composition 
must  remain,  in  essence,  forever  the  same. 

"Dinanzi  a  me  non  fur  cose  create, 
Se  non  eterne,  ed  io  eterno  duro." 

As  it  is  imperishable,  it  may  not  have  been  created. 
In  its  organic  form  it  may  suffer  decomposition  but, 
as  we  have  seen,  the  water,  the  gases,  the  "dust,"  into 
which  it  is  resolved,  is  the  same  matter  in  its  elements  as 
before.  It  has  only  changed  its  form.  The  smoke  and  ashes 
of  matter  consumed  by  fire,  weigh  exactly  as  much,  and  are 
the  same  elements  as  before.  Creation  under  the  natural 
theory  refers  not  to  substance,  but  to  form. 

Facts  in  the  natural  sciences,  which  it  is  not  our  prov- 
ince to  repeat,  enable  us  to  trace  back  the  past  history  of 
our  earth,  through  successive  changes  of  form,  to  a  mass  of 
molten  matter,  irradiating  its  heat  into  space,  until  its  ex- 
terior was  enveloped  in  a  more  or  less  solid  crust.  The  sub- 
sequent condensation  of  steam,  into  which  its  water  had 
been  forced  by  heat,  let  the  rain  fall  upon  the  surface  until 
it  was  wholly  covered  with  water.     The  surging  of  the  mol- 


56  THE  THEORY   OF   EVOLUTION. 

ten  interior  lifted  land  above  the  waters  in  islands,  conti- 
nents and  mountain  chains.  Then,  when  the  heat  had  been 
sufficiently  reduced,  when  water  was  present  in  quantity, 
when  an  atmosphere  (though  not  the  air  we  are  breathing 
now)  floated  above  the  waters,  then — all  the  conditions 
being  present — life  was  developed  in  its  lowest  forms,  as 
inevitably  as  the  heat  was  irradiated,  or  the  steam  condensed, 
or  the  minerals  crystallised  into  special  forms,  or  as  inevitably 
as  any  physical  law. 

The  Theory  of  Evolution. 

That  higher  and  higher  forms  of  life  were  successively 
developed  from  lower  forms,  is  now  abundantly  proven  by 
facts  in  palaeontology,  comparative  anatomy  and  embryology, 
as  well  as  by  direct  observation  of  the  effects  of  natural  and 
artificial  selection. 

Palceontology ,  the  Science  of  Petrifactions, 

or  of  fossils,  furnishes  what  may  be  now  called  indisputable 
proof  of  the  gradual  evolution  of  higher  forms  of  life.  "The 
organisms  buried  in  the  most  ancient  geological  strata  must 
be  looked  upon  as  the  ancestors  from  which  the  rich 
diversity  of  forms  of  the  present  creation  have  originated 
by  continued  generation  and  by  accommodation  to  pro- 
gressive and  very  different  conditions  of  life"  (Carus).  The 
different  strata  of  the  earth,  successively  deposited  at  differ- 
ent epochs  of  time,  may  be  thus  regarded  as  so  many  shelves, 
each  filled  with  specimens  of  synchronous  creation.  Of  the 
vertebrate  animals,  for  example,  we  encounter  first  fish,  then 
amphibious  animals,  then  reptiles,  birds  and  mammals. 

The  explanations  offered  to  account  for  the  existence  of 
fossils  on  any  other  theory  than  that  of  evolution  are  very 
curious.  It  was  believed,  for  instance,  that  fossils  were 
models  in  clay  or  mineral  matter  of  subsequently  improved 


THE   SCIENCE   OF  PETRIFACTIONS.  LI 

creations  in  organic  life.  According  to  others,  petrifactions 
resulted  from  the  influence  of  the  stars  upon  the  interior  of 
the  earth.  "Sports  of  nature,"  they  were  playfully  called. 
Since  we  have  become  acquainted  with  the  vast  denudations 
effected  by  the  action  of  the  air  and  falling  and  running 
water,  we  can  readily  understand  how  forms  of  life  become 
gradually  encrusted  with  sand  and  mud,  and  remain  en- 
tombed for  all  time,  as  indestructible  as  the  subjects  and 
objects  in  Pompeii  and  Herculaneum  while  still  enveloped 
in  ashes  and  lava. 

Though  the  animal  nature  of  fossils  was  recognised  by 
some  of  the  ancient  Greek  philosophers,  notably  by  Xeno- 
phanes,  of  Colophon,  as  also  by  Aristotle,  and  though  even 
the  manner  of  their  petrifaction  seems  to  have  been  under- 
stood by  that  most  versatile  genius  of  the  fifteenth  century, 
Leonardo  da  Vinci,  it  was  not  until  the  beginning  of  the 
present  century  that  their  regular  order  of  deposit  began  to 
be  observed,  so  that  laws  could  be  deduced  to  entitle  palaeon- 
tology to  a  distinct  place  amongst  the  exact  sciences.  AVe 
owe  our  first  definite  knowledge  of  the  deposition  of  these 
ancient  forms  cf  life  to  the  great  natural  philosopher  of 
France,  George  Cuvier.  This  observer  discovered  that  the 
fossils  deposited  last,  that  is,  those  nearest  the  surface  in 
undisturbed  strata,  most  closely  resembled  the  forms  of  life 
now  existing  upon  earth,  whereas  those  deposited  first,  in 
the  deeper  strata,  differed  most  widely  from  living  forms. 
Unfortunately,  Cuvier  wasnot  able  from  this  most  suggestive 
discovery  to  proclaim  the  gradational  development  of  forms 
of  life,  and  thus  anticipate  for  himself  and  his  time  the 
honor  of  the  discovery  of  the  theory  of  descent.  The  differ- 
ences in  the  forms  of  life  encountered  in  different  strata,  he 
believed  to  be  inherent,  and  to  have  been  imprinted  from 
their  birth.  In  other  words,  he  believed  that  each  new  strata 
represented  an  entirely  new  creation  of  all  the  forms  of  life. 


58  THE  CATACLYSMS  OF  CUVIEE. 

The  Cataclysms  of  Cuvier. 

To  account  for  such  extraordinary  phenomena  as  the  ex- 
tinction of  all  existing,  species  and  the  creation  of  new,  he 
invented  the  theory  of  the  cataclysms,  sweeping  revolutions 
or  mighty  casualties  of  nature,  which  at  stated  periods 
suddenly  convulsed  the  earth,  overwhelmed  every  form  of 
life,  and  changed  to  chaotic  confusion  the  whole  face  of  the 
globe.  With  the  restoration  of  order  came  new  forms  of 
life,  different  from  their  predecessors,  to  again  take  possesion, 
until  they,  too,  in  turn  succumbed  in  the  general  crash  of 
another  grand  disaster. 

These  unnatural  cataclysms  of  Cuvier  prevailed  uncontra- 
dicted during  the  first  quarter  of  our  century,  completely 
paralysing  any  hope  of  progress  in  biological  studies,  by  not 
only  recognising  multiple  creations  and  destructions  in  the 
past,  but  providing  also  for  new  ones  in  the  future.  Any 
connected  history  of  development  under  such  an  hypothesis 
was,  of  course,  impossible. 

Closer  observations,  however,  in  physical  geography  began 
to  develop  the  fact  that  changes  were  continually  taking 
place  in  the  level  of  different  regions,  and  in  the  disposition 
of  land  and  water.  Mr.  Croll  and  Mr.  Geike  concluded  from 
the  results  of  their  investigations  that  the  whole  terrestrial 
surface  is  denuded  at  the  rate  of  one  foot  in  six  thousand 
years.  "At  this  rate,  one  foot  in  six  thousand  years,  ten  feet 
in  sixty  thousand  years,  one  hundred  feet  in  six  hundred 
thousand  years  and  one  thousand  feet  in  six  million  years, 
the  Mississippi  river  would  not  require  more  than  about 
four  million  five  hundred  thousand  years  to  wear  away  the 
whole  of  the  North  American  continent,  if  its  mean  height 
is  correctly  estimated  by  Humboldt  at  seven  hundred 
and  forty-eight  feet."  The  potency  of  falling  water  in 
degrading  the  higher  surfaces — a  potency  which,  if  un- 
checked, would  thus  reduce  the  whole  face  of  the  earth  to  a 


THE  GREAT  AGE  OF  THE  EARTH.  59 

common  level  in  a  few  million  years — is  being  continually 
counteracted  by  the  elevating  influence  of  the  molten 
interior  of  our  globe.  The  coast  of  Sweden,  for  example,  is 
observed  to  be  continuously  rising,  while  that  of  Holland  is 
continuously  sinking.  So  constant,  indeed,  must  be  the 
labor  of  man,  in  lifting  off  the  water  from  the  coasts  of 
Holland  as  to  have  given  rise  to  the  saying  there,  that  "God 
made  the  sea,  and  man,  the  shore."  The  west  coast  of  South 
America  has  been  lifted  up  perceptibly  within  the  history 
of  man,  while  the  east  coast  has  sunk  in  the  same  way  in 
the  same  space  of  time.  It  was  the  observation  of  such 
alterations  that  led  the  eminent  geologist,  Robert  Lyell,  of 
England,  to  the  conviction  that  all  the  changes  which  have 
heretofore  taken  place  in  the  physical  geography  of  the 
earth  were  the 

Results  of  Existing  Causes, 

that  is,  those  still  in  operation.  "The  rivers  and  the  rocks, 
the  seas  and  the  continents  have  been  changed  in  all  their 
parts;  but  the  laws  which  direct  those  changes  and  the 
rules  to  which  they  are  subject  have  remained  invariably 
the  same"  (Playfair).  We  may  explain  all  the  phenomena 
of  nature,  said  Generelli,  in  his  address  to  the  Academy  at 
Cimento,  "senza  violenze,  senza  finzioni,  senza  supposti,  senza 
miracoli"  (without  violence,  without  fictions,  without  hy- 
potheses, without  miracles).  These  changes,  which  may  be 
very  slight — a  line  or  an  inch — in  the  life  of  man,  or,  indeed, 
of  mankind,  assume  sufficient  magnitude  in  the  untold  ages 
of  the  past  to  account  for  the  loftiest  peaks  of  mountains  or 
the  greatest  depths  of  the  sea. 

The  Great  Age  of  the  Earth 

is  now  attested  by  a  multitude  of  facts.  Geologists 
claim  to  have   positive  evidence  that   for  at  least  ninety 


60  THE  GREAT  AGE  OF  THE  EARTH. 

millions  of  years,  rain  must  have  fallen  upon  its  surface 
to  effect  the  present  degree  of  denudation.  The  formation 
of  coal  and  of  coral,  of  stalactites  and  stalagmites,  furnish  in- 
disputable evidence  of  the  lapse  of  ages  upon  ages  of  time. 
"Men  are  in  the  habit  of  measuring  the  greatness  and  the 
wisdom  of  the  universe  by  the  duration  and  the  profit 
which  it  promises  to  their  own  race ;  but  the  past  history 
of  the  earth  already  shows  what  an  insignificant  moment 
the  duration  of  the  existence  of  our  race  upon  it  constitutes. 
A  Nineveh  vessel,  a  Eoman  sword  awakens  in  us  the  con- 
ception of  gray  antiquity.  What  the  museums  of  Europe 
show  of  the  remains  of  Egypt  and  Assyria  we  gaze  upon 
with  silent  astonishment,  and  despair  of  being  able  to  carry 
our  thoughts  back  to  a  period  so  remote.  Still  must  the 
human  race  have  existed  for  ages  and  multiplied  itself 
before  the  pyramids  of  Nineuch  could  have  been  erected. 
We  estimate  the  duration  of  human  history  at  6000  years; 
but  immeasurable  as  this  time  may  appear  to  us,  what  is  it 
in  comparison  with  the  time  during  which  the  earth  carried 
successive  series  of  rank  plants  and  mighty  animals  and  no 
men  ;  during  which  in  our  neighborhood  the  amber  tree 
bloomed  and  dropped  its  costly  gum  on  the  earth  and  in 
the  sea ;  when  in  Siberia,  Europe  and  North  America  groves 
of  tropical  palms  flourished;  where  gigantic  lizards,  and 
after  them  elephants,  whose  mighty  remains  we  still  find 
buried  in  the  earth,  found  a  home  ?  *  *  *  *  And  the 
time  during  which  the  earth  generated  organic  beings  is 
again  small  when  we  compare  it  with  the  ages  during  which 
the  world  was  a  ball  of  fused  rocks.  For  the  duration  of  its 
cooling  from  2000°  to  200°  centigrade,  the  experiments  of 
Bishop  upon  basalt  show  about  350  millions  of  years  necessary. 
And  with  regard  to  the  time  during  which  the  first  nebulous 
mass  condensed  into  our  planetary  system  our  most  daring 
conjectures  must  cease.     The  history  of  man,  therefore,  ia 


GItADATIONAL  EVOLUTION  OF  FORM.  61 

but   a  short   ripple   in   the   ocean   of  time"  (Helmholtz). 

It  is  only  necessary  to  appreciate  the  great  age  of  the  earth  to 
understand  the  might  of  the  slow  and  silent  changes  in  per- 
petual operation,  and  to  realise  the  truth  of  the  remark  that 
"changes  which  are  rare  in  time  are  frequent  in  eternity." 

It  was  this  revalation  of  the  order,  instead  of  disorder, 
observed  in  the  history  of  the  development  of  the  inorganic 
world  that  enabled  palaeontologists  to  disclose  in  fossils  the 

Gradational  Evolution  of  Forms  of  Life. 

It  is  only  within  the  past  twenty  years  that  proof  of  this 
fact  has  received  its  highest  confirmation  in  the  accumula- 
tion of  evidence  of  the  existence  of  man  in  ages  antedating 
any  historical  record.  It  may  be  stated  as  now  beyond 
question  that  "not  only  man,  but,  what  is  more  to  the  pur- 
pose, intelligent  man,  existed  at  times  when  the  whole 
physical  conformation  of  the  country  was  totally  different 
from  that  which  characterises  it  now."  And  the  fact  itself 
that  the  difference  is  so  slight  between  the  most  ancient 
remains  of  human  forms  as  yet  discovered — the  celebrated 
Neanderthal  skull  for  instance — and  the  forms  now  upon 
the  surface  of  the  earth,  is  most  conclusive  evidence  of  the 
time  required  to  effect  any  very  great  change  in  the  physical 
conformation  and  constitution  of  our  earth.  The  horse, 
which  now  exists  is  the  same  in  all  essential  regards  as  the 
horse  of  .the  period  of  time  referred  to,  but  is  a  very  different 
animal  from  the  horse  of  a  much  more  ancient  period.  It 
was  the  recognition  of  the  eras  of  time  necessary  to  effect 
radical  changes  in  the  structure  of  animal  forms  under  the 
slow  agencies  of  natural  selection  that  forced  upon  scientists 
the  conviction  that  no  series  of  sudden  catastrophes  or 
convulsions  have  marked  or  marred  the  even  course  of 
nature.  As  Mr.  Huxley  has  remarked :  "Catastrophic 
palaeontologists    are    now    practically   extinct."    It    may 


62  GRADATION  AL  EVOLUTION   OF  FORM. 

not  be  said,  indeed,  that  our  record  is  in  all  respects 
complete.  When  we  consider  the  disturbing  eleva- 
tions and  depressions  to  which  all  parts  of  the  earth  have 
been  repeatedly  subjected,  the  yery  small  extent  of  surface 
as  yet  explored — not  the  one-thousandth  part  of  the  whole 
— the  metamorphic  changes  which  heat  has  induced  in  the 
lowest  strata  of  rock,  and  when  we  recall  the  perishability 
of  intermediate  forms,  and  of  all  except  the  hardest  parts  of 
all  forms,  we  cease  to  wonder  at  the  "missing  links."  Many 
of  the  specimens  still  preserved  are  in  sadly  mutilated 
state,  like  the  wounded  in  the  broken  ranks  at  the  roll 
call  after  battle.  But  the  losses  are  compensated  in  some 
degree  by  the  skill  of  the  interpreters.  Some  of  you  are 
doubtless  familiar  with  the  story  of  Zadig  in  the  Eomances 
of  Voltaire.  He  was  a  youth  who  had  "chiefly  studied  the 
properties  of  plants  and  animals,  and  soon  acquired  a  sagacity 
that  made  him  discover  a  thousand  differences,  when  other 
men  see  nothing  but  uniformity."  The  light  and  long 
furrows  impressed  upon  the  sand  between  the  marks  of  the 
paws,  revealed  to  him  that  the  animal  escaped  was  a  bitch 
recently  whelped  ;  other  side  traces  told  of  the  hanging  ears 
of  a  spaniel,  and  the  slighter  impression  of  one  of  the  paws 
showed  that  the  animal  was  a  little  lame.  Thus  also  he  was 
able  to  divine  the  height  of  a  runaway  horse,  the  length  of 
his  tail,  the  character  of  his  shoes  and  bit,  in  a  manner  to 
astound  his  questioners,  and,  as  has  often  happened  since, 
under  similar  circumstances,  to  render  him  liable  to  persecu- 
tion for  sorcery.  But  how  much  more  incredible  and  incom- 
prehensible to  the  unlearned  is  the  more  definite  and  extensive 
knowledge  afforded  by  a  footprint  to  the  palaeontologist  or  com- 
parative  anatomist?  "Whoso  sees  merely  the  print  of  a  cleft 
foot,"  wrote  Cuvier,  "may  conclude  that  the  animal  which 
left  this  impression  ruminated,  and  this  conclusion  is  as 
certain  as  any  other  in  physics  or  morals.    This  footprint 


GRADATIONAL  EVOLUTION  OF  FORM.        63 

alone  yields  to  him  who  observes  it,  the  form  of  the  teeth, 
the  form  of  the  jaws,  the  form  of  the  vertebra?,  the  forms 
of  all  the  bones  of  the  legs,  of  the  thighs,  of  the  shoulders 
and  of  the  pelvis  of  the  animal  which  has  passed  by  ;  it  is 
a  surer  mark  than  all  those  of  Zadig."  A  fossil  fragment 
of  a  lower  jaw  directly  attached  to  a  piece  of  skull  would 
enable  the  palaeontologist  as  positively  to  assert  that  the 
animal  of  which  the  fragment  was  part  had  two  occipital 
condyles  with  an  ossified  basi-occipital  bone,  had  also  red 
corpuscles  in  its  blood  and  breasts  to  suckle  its  young. 

Thus  the  excavation  of  a  few  fossil  bones  of  the  leg  in 
our  country  completed  the  line  of  descent  of  the  horse,  the 
discovery  of  a  couple  of  small  back  teeth  (of  a  predatory 
marsupial)  in  the  Trias  formation  established  the  existence 
of  mammals  at  that  early  period  of  time,  and  the  im- 
perfect impression  from  the  Jura  of  a  fossil  bird  (the 
archseopteryx)  with  a  lizard's  tail  confirmed  the  con- 
jecture previously  made  that  birds  were  developed  from 
lizards.  Thus  from  a  fragment  of  bone  or  a  tooth,  from  a 
feather  or  a  footprint,  has  been  deciphered,  as  from  ancient 
hieroglyphics,  the  gradational  development  of  animal  life. 

For  my  part,  said  Mr.  Darwin,  in  speaking  of  the  imper- 
fection of  the  geological  record,  for  my  part,  following  out 
Ly ell's  metaphor,  I  look  at  the  geological  record  as  a  history 
of  the  world  imperfectly  kept  and  written  in  a  changing 
dialect ;  of  this  history  we  possess  the  latest  volume  alone, 
relating  only  to  two  or  three  countries.  Of  this  volume, 
only  here  and  there  a  short  chapter  has  been  preserved  ,  and 
of  each  page,  only  here  and  there  a  few  lines.  Each  word 
of  the  slowly  changing  language,  more  or  less  different  in  the 
successive  chapters,  may  represent  the  forms  of  life  which  are 
entombed  in  our  consecutive  formations  and  which  falsely  ap- 
pear to  us  to  have  been  abruptly  introduced.  On  this  view  the 
difficulties  discussed  are  greatly  diminished  or  even  disappear. 


64  THE  EVOLUTION  OF  FORMS  OF  LIFE. 


LECTURE    IV. 


THE  EVOLUTION  OF  FORMS  OF  LIFE. 

CONTENTS. 

Comparative  Anatomy— Of  the  Eye  and  the  Ear— Order  of  Develop- 
ment—Jean Lamarck — Wilhelm  von  Goethe— The  Intermaxillary 
Process— Erasmus  Darwin— Anatomical  Resemblances— The  Hand 
and  its  Homologues— Comparative  Embryology— Ernst  Haeckel— 
The  Rudimentary  Organs— Bone  Rudiments— Muscle  Rudiments — 
Rudiments  from  the  Digestive  System— Other  Rudiments— Explana- 
tions of  Rudiments. 

To-day  we  approach  the  development  of  life  from  the 
standpoint  of 

Comparative  Anatomy. 

The  most  striking  feature  in  a  general  survey  of  the  forms 
of  life  is  their  almost  infinite  diversity.  The  mind  is  fairly 
confused  in  its  attempt  to  review  the  vast  procession  of  ani- 
mated beings  in  constant  defile  about  us,  having  nothing 
more  in  common,  apparently,  than  motion  or  growth,  repro- 
duction or  assimilation,  the  grosser  phenomena  of  life. 
Humboldt  estimated,  many  years  ago,  that  there  were  56,000 
species  of  plants  and  51,700  species  of  animals.  We  know 
now  that  species  are  numberless  because  they  are  mutable. 
It  is  comparative  anatomy  alone  that  reveals  to  us  the  simi- 
larity of  structure  pre vading  all  these  forms,  notwithstanding 
their  great  diversity  in  external  appearance.  By  the  study 
of  comparative  anatomy  we  are  thus  enabled  to  group  the 
forms  of  life  into  species,  genera  and  tribes,  to  single  out 
elements  or  types  of  structure  from  which  all  the  various 
forms  are  modeled,  however  much  they  vary  to  superficial 
inspection,  and  to  trace  the  points  of  resemblance  to  and 


Fig.  i. — Man,  iv  weeks.  Fig.  2. — Dog,  iv  weeks. 


Fig.  5. — Ccecum  and  vermi- 
form appendix,  c,  small  in- 
testine, e,  large  intestine.  </, 
ileo-ccecal  valve,  c,  orifice, 
and  b,  termination  of  vermi- 
form appendix,     (p.  80) 


Fig.  6. — Eve.  a.  plica  semi- 
lunaris, rudimentary  nictitat- 
ing membrane,     (p.  80) 


Fig.  3. — Chick,  iv  days.  Fig.  4. — Tortoise,  iv  weeks. 

THE   VERTEBRATE    FCETUS.     (p.   74.) 


Fig.  7. — Pelvis,     o,  coccyx,  rudimentary  cau-      Fig.  8.— Ear.     b,  extrinsic,  and  a. ,  intrin- 
dal  extremity.     (,p.  78)  sic  (rudimentary)  muscles,     r,  position  of 

point  of  ear  turned  in.     (p.  81) 

RUDIMENTARY     ORGANS. 


THE  ORGAN   OF  VISION.  65 

divarication  from  the  archetypal  plan.  Cuvier  has  happily 
compared  the  examination  of  the  comparative  anatomy  of 
an  organ,  in  its  gradation  from  its  simplest  to  its  most  com- 
plex state,  to  an  experiment  which  consists  in  removing 
successive  portions  of  the  organ,  with  a  view  to  determine 
its  most  essential  and  important  part.  In  the  animal  series 
we  see  this  experiment  performed  by  the  hand  of  nature, 
without  those  disturbances  which  mechanical  violence  must 
inevitably  produce.  We  thus  learn  from  comparative 
anatomy,  that  the  vestibule  is  the  fundamental  part  of  the 
organ  of  hearing ;  and  that  the  other  portions,  the  semi- 
circular canals,  the  cochlea,  the  tympanum  and  its  contents, 
are  so  many  additions  made  successively  to  it,  according  as 
the  increasing  perceptive  powers  of  the  animals  rendered  a 
more  delicate  acoustic  organ  necessary. 

Comparative  anatomy  thus  discloses  the  development  and 
differentiation  of  all  the  various  organs,  from  the  most 
simple  elementary  forms  to  the  most  finished  and  compli- 
cated structure,  and  at  the  same  time  reveals  the  regular 
order  of  addition  o'f  parts  on  the  road  to  gradual  perfection. 

We  might  select,  for  example,  the  complex  and  composite 
structure  of  the 

Organ  of  Vision, 

wdiich,  if  regarded  only  in  its  nearly  perfected  state,  as  in 
man  or  birds,  would  seem  to  have  required  separate  and 
independent  creation  in  the  body  in  which  it  is  found.  But 
comparative  anatomy,  in  tracing  down  the  structure  of  the 
eye,  shows  us  the  gradual  reduction  of  parts  and  brings  us 
at  last  to  the  simplest  possible  arrangement  of  cells  which 
could  serve  for  visual  purpose. 

Thus,  lowest  in  the  scale  of  living  beings,  among  the 
protozoa,  we  find  simply  a  collection  of  pigment  cells,  with- 
out any  nervous  structure  whatever,  resting  upon  sensitive 


66  JEAN   LAMARCK. 

protoplasm.  In  star-fishes  the  pigment  cells  are  depressed 
and  the  cavities  filled  with  gelatinous  matter  to  constitute 
primitive  lenses  and  to  effect  the  first  concentration  of  light. 
In  articulate  animals  an  optic  nerve  is  coated  with  pigment 
sometimes  arranged  in  the  form  of  a  pupil.  In  insects  are 
superadded  numerous  facets,  each  a  distinct  lens  to  converge 
the  rays  of  light  upon  the  sensitive  nerve  filaments  beneath. 
In  the  lowest  vertebrate  animal,  the  lancelet,  we  start  with 
"a  little  sack  of  transparent  skin,  furnished  with  a  nerve 
and  lined  with  pigment,  but  destitute  of  any  other  appa- 
ratus." As  we  ascend  the  scale  of  vertebrata  we  successively 
encounter  the  more  or  less  developed  crystalline  lens,  the 
vitreous  and  aqueous  bodies  (additional  lenses),  the  retina 
with  rods  or  cones,  or  both,  and,  finally,  the  accessory  appa- 
ratus of  muscles  and  lids  and  lashes,  glands  for  the  manu- 
facture of  lubricating  oil  and  tears,  and  tubes  to  convey 
away  superfluous  fluids. 

What  is  true  in  this  way  of  organs  in  the  body  is  true  of 
the  whole  body,  that  is  of  the  position  it  occupies  in  the 
animal  scale.  We  may  observe  in  the  study  of  comparative 
anatomy,  the 

Order  of  Succession 

of  different  animals  in  a  progressive  and  uninterrupted  chain. 
In  the  vertebrate  animals,  for  instance,  we  see  this  succession 
maintained  from  fishes  to  amphibia,  reptiles,  birds  and  mam- 
mals, and  from  the  lower  to  the  higher  orders  of  each  class. 
Comparative  anatomy  pays  its  highest  tribute  to  biology 
in  displaying  the  general  unity  of  structure  in  the  various 
forms  of  life.  We  owe  the  first  definite  exposition  of  this 
principle  to  the  distinguished  French  philosopher, 

Jean  Lamarck. 

In  the  earliest  years  of  the  present  century  Lamarck  pub- 
lished in  Paris  his  Zoological  Philosophy,  which  was  accord- 


JEAN   LAMARCK.  67 

ing  to  its  title  "an  exposition  of  the  natural  history  of  ani- 
mals showing  the  diversity  of  their  organization  and  faculties 
the  physical  causes  which  maintain  them  in  life,  give  rise  to 
the  movements  they  may  execute   and  endow  them  with 
sentiment  and  intelligence."     Lamarck  first  propounded  the 
theory  of  descent  in  his  Natural  History  of  Invertebrated 
Animals — 1815 — 1822.     In  this  work  he   maintained  that 
"the  systematic  divisions  of  classes,  orders,  families,  genera 
and  species,  as  well  as  their  designations,  are  the  arbitrary 
and  artificial  productions  of  man.     The  kinds  or  species  of 
organisms  are  of  unequal  age,  developed  one  after  another 
and  show  only  a  relative  and  temporary  persistence.   *   *  * 
The  differences  in  the  conditions  of  life  have  a  modifying 
influence  on  the  organization,  the  general  form  and  the  parts 
of  animals,  and  so  has  the  use  and  disuse  of  organs.     In  the 
first  beginning,  only  the  very  simplest  and  lowest  animals 
and  plants  came  into  existence;  those  of  a  more  complex 
organization  only  at  a  later  period.     The  cause  of  the  earth's 
development  and  that  of  its  organic  inhabitants,  was  con- 
tinuous,  not  interrupted  by  violent   revolutions.     Life   is 
purely  a  physical  phenomenon.     All  the  phenomena  of  life 
depend  on  mechanical,  physical  and  chemical  causes,  which 
are   inherent   in   the   nature  of   matter  itself."     Lamarck 
is    therefore    justly    regarded    as    the    originator    of    the 
theory  of  evolution  or  the  doctrine  of  descent.     His  views 
excited,    however,    but    little    attention   at    the    time    of 
publication.     Lamarck  had  no  idea   of    the    struggle  for 
existence   entailed  by   numbers  and   the   survival  of   the 
fittest,   the  key   notes   in  the   comprehension   of  the  doc- 
trine  of    descent;    still   for  having    proposed   the   theory 
and    backed    it    with    proof    from  comparative   anatomy, 
Lamarck  must   always  be  regarded  as  the  pioneer  in  this 
great  discovery. 

Almost  about  the  same  time,  the  doctrine  of  unity  of 


6$  WILHELM   WOLFGANG   VON   GOETHE, 

structure  was  occupying  the  attention  of  the  greatest  intel- 
lect in  Germany, 

Wilhelm   Wolfgang  von  Goethe. 

We  are  all  fully  familiar  with  the  literary  achievements  of 
Goethe,  whom  we  are  accustomed  to  regard  as  second  only 
to  Shakespeare  as  a  delineator  of  human  feelings  and  pas- 
sions, but  few  of  us  are  aware  that  he  far  surpassed  Shake- 
speare in  his  deeper  and  more  subtile  conceptions  of  the 
secrets  of  nature — the  result  of  higher  culture  in  the  physical 
sciences  of  his  day.  In  his  persistent  search  after  a  type  of 
structure  in  the  vegetable  world  he  had  already  hit  upon 
the  leaf — and  would  have  reached  the  cell,  no  doubt,  had 
the  microscope  been  in  general  use — when  he  directed  his 
attention  to  the  study  of  animal  life.  From  his  investiga- 
tion into  the  structure  of  insects  he  was  able  to  announce 
the  ring,  a  succession  of  which,  from  the  head  to  the  tail, 
constitutes  the  whole  body,  to  be  the  fundamental  principle, 
modified  only  to  form  the  various  parts  of  the  animal. 
What  the  leaf  was  to  the  plant,  was  the  ring  to  the  insect. 
So  the  vertebra  is  the  starting  point  or  ground  principle  for 
the  vertebrate  animal.  But  for  a  long  time  the  bones  of  the 
cranium  confused  him.  They  seemed  so  entirely  different 
from  all  other  osteological  forms  in  the  body  "as  to  trans- 
port him,"  as  he  said  when  attempting  to  deduce  them  from 
vertebrae,  "into  a  sort  of  frenzy."  A  bleached  sheep's  skull 
picked  up  in  the  Jewish  cemetery  at  Venice,during  one  of  these 
perturbed  meanderings,  revealed  to  him  as  in  a  flash  of  in- 
spiration the  derivation  of  the  cranium  from  the  vertebral 
bones.  Though  this  view  has  since  undergone  much  modi- 
fication, it  was  of  the  highest  value  in  its  day  in  concen- 
trating the  attention  of  the  scientific  world  upon  the  funda- 
mental principles  underlying  all  animal  structure.  There 
remains  still  another  discovery  of  Goethe,  worthy  of  especial 


THE   INTER-MAXILLARY   PROCESS.  69 

mention  in  this  connection,  a  genuine  discovery,  which  no 
later  developments  may  ever  confute.  It  is  to  Goethe  that 
we  owe  the  discovery  in  man  of  the  so-called  mid  jawbone, 

The  Inter- Maxillary  Process, 

supporting  the  upper  incisor  teeth,  found  constantly  in  most 
lower  animals  in  the  class  of  mammals,  but  up  to  the  time 
of  Goethe,  never  detected  in  man.  "The  strange  case  now 
occurred,"  wrote  Goethe,  "that  the  distinction  between  apes 
and  men  was  made  by  ascribing  an  inter-maxillary  bone  to 
the  former  and  none  to  the  latter  ;  but  as  this  part  is  mainly 
remarkable  because  the  upper  incisor  teeth  are  set  in  it,  it 
was  inconceivable  how  man  should  have  the  incisor  teeth 
and  lack  the  bone."  Goethe  therefore  determined  that  man 
must  possess  the  inter-maxillary  bone  and  began  his  search 
for  it  in  every  skull  that  came  in  his  way.  After  examin- 
ing a  great  number  of  skulls  he  found  it  at  last  an  inde- 
pendent bone.  Every  skull  possesses  it,  but  as  age  advances 
it  unites  with  the  superior  maxilla  so  closely  that  even 
the  line  of  union,  like  that  of  the  halves  of  the  frontal 
bones,  is  completely  lost  to  view.  During  the  whole  of 
foetal  life  it  may  be  readily  demonstrated  in  every  case, 
often  too  in  early  infancy  it  remains  still  isolated  except  by 
membranous  connection,  but  only  as  the  greatest  rarity  may 
it  be  observed  in  later  life.  Goethe  was  so  fortunate  as  to 
encounter  such  an  unanchylosed  specimen  and  thus  could 
forge  another  link  in  the  chain  of  evidence  for  the  theory  of 
descent.  "Thus  much,"  said  Goethe  in  summing  up  his 
views  on  animal  life,  "thus  much,  then,  we  have  gained, 
that  we  may  assert -without  hesitation  that  all  the  more 
perfect  organic  natures,  such  as  fishes,  amphibious  animals, 
birds,  mammals,  and  man  at  the  head  of  the  last,  were  all 
formed  upon  one  original  type,  which  only  varies  more  or 
less  in  parts,  which  are   none  the  less  permanent,  and  still 


70  ERASMUS   DARWIN. 

daily  changes  and  modifies  its  form  by  propagation."  No 
one  has  so  tersely  expressed  the  power  of  adaptation  or 
adjustment  to  external  circumstances  as  Goethe  when  he 
said  "the  animal  is  formed  by  circumstances  for  circum- 
stances." 

This  same  thought  had,  however,  already  found  expression 
in  a  different  tongue  in  a  different  part  of  the  civilized  world. 

Erasmus  Darwin, 

the  grandfather  of  the  author  still  living,  whose  name  is 
now  known  everywhere,  had  arrived  at  the  same  conclusions 
without  any  knowledge  of  the  labors  of  Goethe  or  Lamarck. 
The  doctrine  of  descent  "pervaded  the  air,"  one  might  say, 
on  observing  its  almost  simultaneous  enunciation  in  Ger- 
many, England  and  France.  Erasmus  Darwin  published 
his  Zoonomia  in  1795,  already  recognizing  at  this  early 
period  the  changing  structure  of  animal  life  under  changing 
external  conditions. 

Such  is,  in  brief,  the  early  history  of  the  filiation  theory 
in  its  relation  to  comparative  anatomy.  When  we  come 
now  to  observe  for  ourselves  the 

Anatomical  Resemblance 

between  man  and  the  lower  animals,  we  are  struck  with 
amazement  that  their  relationship  was  not  noticed  long 
before.  The  whole  structure  of  the  skeleton  is  glaringly 
similar  among  all  the  vertebrate  animals.  Confining  our- 
selves to  the  highest  types,  we  observe  such  close  resem- 
blance between  the  bones  of  man  and  anthropoid  apes  as  to 
require  intimate  knowledge  of  comparative  anatomy  to 
declare  which  is  which.  The  same  remark  might  be  made 
of  all  the  internal  organs.  The  difference  between  the  brain 
of  man  and  apes  is  much  less,  said  Vulpian,  than  between 
that   of  apes  and  the  quadrumana  just  below  them.     We 


ANATOMICAL  RESEMBLANCES.  71 

find,  indeed,  less  difference  in  bodily  structure  and  mental 
faculties  between  higher  and  lower  apes  than  between  higher 
and  lower  species  or  races  of  man.  The  refinements  of 
chemistry  and  spectroscopy  have  not  been  able  to  differenti- 
ate the  blood  of  man  from  that  of  lower  animals.  The 
microscope  refuses  to  note  a  distinguishing  point  between 
the  blood  corpuscles  of  man  and  the  dog.  Finer  evidence 
even  than  this,  the  same  medicines,  and  the  same  diseases 
produce  the  same  effects.  Post-mortem  sections  reveal  to  us 
the  same  lesions  of  structure  in  apoplexies,  phthises,  hepatic 
diseases,  brain  affections,  etc.,  common  to  all  the  higher 
forms  of  life.  "Many  kinds  of  monkeys,"  Mr.  Darwin  re- 
lates, "have  a  strong  taste  for  tea,  coffee  and  spirituous 
liquors  ;  they  will  also,  as  I  have  myself  seen,  smoke  tobacco 
with  pleasure."  The  same  author  quotes  from  Brehm  the 
assertion,  that  the  natives  of  northeastern  Africa  catch  the 
wild  baboons  by  exposing  vessels  with  strong  beer,  by  which 
they  are  made  drunk.  They  suffer  also  the  same  scourges  for 
these  pleasant  vices,  for  monkeykind  endure  "katzenjammer" 
on  the  next  morning  in  common  with  mankind.  But  Brehm 
tells  the  story  of  an  American  monkey  who  after  getting 
drunk  on  brandy,  would  never  touch  it  again,  and  thus  was 
wiser  than  many  men.  The  taste  nerves  and  the  whole 
nervous  system,  therefore,  is  the  same  in  the  monkey  as  in 
man.  Carl  Vogt  concludes  from  his  numerous  investigations 
that  there  is  no  doubt  whatever  that,  according  to  the 
fundamental  part  of  the  brain,  man,  belongs  to  the  ape. 
On  comparing,  says  Gratiolet,  a  series  of  human  and  simian 
brains,  we  are  immediately  struck  with  the  analogy 
exhibited  in  the  cerebral  forms  in  all  these  creatures.  The 
convoluted  brain  of  man  resembles  the  smooth  brain  of  the 
ouistitis  in  the  characteristics  of  a  rudimentary  olfactory 
bulb ;  a  posterior  lobe,  which  entirely  covers  the  cerebellum  ; 
a  perfectly  marked  Sylvian  fissure,  and  a  posterior  cornu 


72  THE  HAND  AND  ITS  HOMOLOGUES. 

in  the  lateral  ventricle  of  the  brain.  And  he  might  have 
added,  adds  Vogt,  the  existence  of  a  central  or  intermediate 
lobe  which  occurs  in  all  apes.  "Thus  there  is  a  cerebral 
form  peculiar  to  man  and  ape ;  and  so  in  the  cerebral 
convolutions,  wherever  they  appear,  there  is  a  general  unity 
of  arrangement — a  plan,  the  type  of  which  is  common 
to  all  these  creatures"  (Gratiolet).  "But,"  Bischoff  persists, 
"there  is  no  time  when  we  may  not  differentiate  the  brain  of 
a  monkey  from  that  of  a  man."  "True,"  replies  Mr.  Darwin, 
"else  a  monkey  would  be  a  man."  The  difference  is  only 
difference  in  degree.  As  long  ago  observed  by  Wundt,  ani- 
mals are  creatures  whose  intelligence  differs  from  men  only 
by  the  degree  of  development.  There  exists  between  men 
and  brutes  (mutes  is  a  better  word),  no  wider  gulf  than  is 
to  be  found  within  the  animal  kingdom  itself.  All  animated 
organisms  form  a  chain  of  connected  beings  without  an 
interval.  It  is  only  "an  antiquated  psychology,  with  its 
great  variety  of  mental  faculties,  which  draws  here  and 
there  lines  of  demarcation." 

Man  belongs  to  the  division  of  vertebrates,  the  class 
of  mammifera  and  the  order  of  apes.  But  it  is  known  that 
man  did  not  descend  from  any  of  the  existing  anthropoid 
apes.  No  naturalist  now  maintains  this  view.  Man  is 
known  to  have  descended  from  acatarrhine  ape  with  pointed 
ears,  a  hairy  skin,  a  caudal  extremity,  arboreal  in  habit,  an 
ancestral  form,  common  to  man  and  to  existing  apes.  Nearly 
ten  years  ago,  Dr.  Barrago  Francesco  published  a  work, 
bearing  in  Italian  the  title,  "Man  made  in  the  image  of  God, 
was  also  made  in  the  image  of  the  ape." 

The  Hand  and  its  Homologues. 

Perhaps  no  part  of  the  body  will  furnish  a  more  satis- 
factory demonstration  of  the  unity  of  structure,  notwith- 
standing the  difference  of  external  form,  than  the  termination 


COMPARATIVE  EMBRYOLOGY.  73 

of  the  upper  extremity,  the  hand  in  man  or  its  homologue 
in  lower  animals.  If  Ave  compare  in  this  way  the  hand  of  man 
with  that  of  the  gorilla  and  orang,  with  the  forepaw  of  the 
dog,  the  flipper  of  the  seal  and  dolphin,  the  wing  of  the  bat, 
the  shovel  foot  of  the  mole  and  the  forefoot  of  the  duck-bill, 
we  shall  find  them  to  be  composed  of  exactly  the  same  bones, 
arranged  in  exactly  the  same  order,  with  exactly  the  same 
connections.  The  breadth  and  thickness  of  the  thumb  in 
the  gorilla,  so  much  approach  that  of  man,  that,  as  Mr. 
Huxley  justly  observes,  there  is  more  dissimilarity  between 
the  hand  of  the  orang,  which  has  one  bone  more  in  the  carpus, 
and  that  of  the  gorilla,  than  between  the  hand  of  the  gorilla 
and  that  of  man.  Indeed,  the  hand  of  man,  the  highest  of 
mammals,  more  closely  resembles  the  fore  extremity  of  the 
duck-bill,  the  lowest  of  mammals,  than  any  of  the  intervening 
types.  As  with  the  hand,  so  it  is  with  every  other  member 
or  organ  in  the  body,  the  similarity  of  fundamental  struc- 
ture betrays  the  kinship,  the  inheritance  from  the  common 
ancestral  type 

Comparative  Embryology. 

But,  comparative  anatomy  only  sheds  its  full  illumination 
over  the  field  of  biology  when  its  light  is  turned  upon  every 
stage  and  phase  of  life.  Hitherto  it  is  only  adult  or  mature 
forms  that  have  been  thought  worthy  of  any  consideration. 
In  quite  recent  years  undiscovered  treasure  has  been  dis- 
closed in  embryonic  life,  a  phase  of  existence  almost  wholly 
ignored,  or  at  least  studied  only  by  the  privileged  few. 
What  makes  comparative  embryology  especially  profitable 
in  the  study  of  the  development  of  forms  of  life,  is  the  fact 
that  changes  of  structure  occur  in  the  embryo  with  such 
very  great  rapidity.  The  transformations  of  maturer 
types,  which  geological  ages  required  to  effect  under  the 
slow  agencies  of  natural  selection,  are  run  through  in  the 

7 


74  COMPARATIVE  EMBRYOLOGY. 

foetus  in  a  few  weeks  or  months.  Thus  we  may  observe, 
at  different  stages  of  foetal  life,  phases  of  development 
and  evolution,  for  whose  recognition  in  mature  forms 
we  must  appeal  to  the  faulty  records  of  the  prim- 
aeval world.  It  is  in  the  respect  of  its  completeness, 
thus,  that  the  evidence  furnished  by  embryology  is  so  much 
superior  to  that  of  palaeontology.  And  for  this  evidence  it 
may  be  claimed  with  equal  truth  that  it  has  not  been 
"tampered  with  by  the  hand  of  man." 

Although  the  main  facts  in  our  present  knowledge  of 
embryology  had  been  divulged  as  long  as  a  century  and  a 
half  ago  by  the  eminent  German  naturalist,  Caspar  Wolff, 
and  although  the  full  history  of  embryonic  development  of 
animals  had  been  exhaustively  studied  by  Pander  and  Bar 
within  the  first  quarter  of  this  century,  yet  it  was  not  until 
the  present  decade,  our  own  day,  as  it  were,  that  we  have 
become  familiar,  through  the  labors  of 

Ernst  Haechel,  of  Jena, 

with  the  developmental  phenomena  of  foetal  life,  and  their 
significance  in  comparative  anatomy.  Haeckel  conceived 
the  happy  idea  of  placing  accurate  representations  of  the 
foetus  of  different  animals,  including  man,  in  parallel  columns 
that  their  resemblance,  one  might  almost  say,  identity  of 
form  and  structure,  should  be  apparent  at  a  glance.  No  one 
may  look  upon  these  representations  of  the  foetus  of  man, 
the  dog,  the  chicken  and  the  tortoise,  with  an  unprejudiced 
eye,  and  fail  to  be  convinced  of  their  unity  of  structure. 
The  general  conformation,  the  position  of  the  upper  and 
lower  extremities,  are  the  same  in  every  foetus;  the  various 
vesicles  of  the  brain  are  alike  present  in  each ;  the  organs 
of  the  senses  and  the  viscera  are  similarly  located  and  dis- 
posed ;  and  each  has  a  caudal  termination  projecting  between 
the  lower  extremities. 


COMPARATIVE  EMBRYOLOGY.  75 

Perhaps  the  most  striking  feature  common  to  every  foetus 
is  the  row  of  branchial  clefts  ou  the  under  and  lateral  sur- 
face of  the  neck.  The  human  foetus  presents  these  fissures 
as  distinctly  as  every  other.  But  it  is  only  in  the  fish  that 
these  clefts  persist  to  become  developed  into  the  gill  arches 
supporting  the  leaves  formed  by  the  ramifying  pulmonary 
vessels,  "the  fishes  ears,"  properly,  its  lungs.  The  gill 
arches  of  the  human  and  most  other  vertebrate  foetus  are 
subsequently  absorbed  in  the  formation  of  the  jaw  and  organ 
of  hearing,  but  their  existence  at  an  early  period  of  embryo 
life  is  incomprehensible  in  any  other  light  than  that  of  con- 
struction upon  the  same  fundamental  plan.  At  a  still 
earlier  period  in  the  life  of  the  human  foetus,  the  arteries 
run  in  arches  to  these  branchial  clefts  and  some  time  after 
the  superfluous  arches  have  shriveled  away,  the  branchial 
clefts  still  remain  as  landmarks  of  their  former  place.  The 
arch  of  the  aorta,  and  the  arches  of  the  subclavian  arteries, 
are  the  last  relics  of  the  vascular  arches  of  earlier  dates. 

In  the  human  foetus,  as  in  that  of  all  vertebrate  animals, 
the  heart  is  at  first  only  a  dilatation  of  the  aorta,  a  simple, 
spindle-shaped,  pulsatile  vessel  without  septa  or  valves. 
The  human  foetus  has  also,  in  common  with  the  rest,  a  pair 
of  Wolffian  bodies,  in  lieu  of  kidneys,  and  its  excreta,  like 
the  rest,  are  voided  through  a  cloacum.  The  convolutions 
of  the  brain  of  the  human  foetus  at  the  seventh  month 
nearly  exactly  correspond  to  those  of  the  adult  baboon. 
Mr.  Huxley  makes  the  remark,  that  it  is  only  "quite  in  the 
later  stages  of  development  that  the  young  human  being 
presents  marked  differences  from  the  young  ape,  while  the 
latter  departs  as  much  from  the  dog  in  its  developments  as 
man  does.  Startling  as  this  last  assertion  may  appear  to  be, 
it  is  demonstrably  true." 

Embryology  reveals  to  us  the  significance  of  organs  and 
structures  like  the  Wolffian  body  and  ductus  venosus,  or 


76  COMPARATIVE  EMBRYOLOGY. 

urachus,  etc.,  and  at  the  same  time  reconciles  otherwise  dis- 
cordant features  in  comparative  anatomy.  The  develop- 
ment and  formation  of  the  lower  extremity  may  serve  as  an 
example.  The  similarity  of  structure  of  the  upper  extremity 
among  all  vertebrate  animals  has  already  been  mentioned. 
It  is  easy  to  recognize  the  same  bones,  in  the  same  order, 
arrangement  and  connection,  etc.  But  in  the  lower  ex- 
tremity this  harmony  is  apparently  not  observed.  Thus, 
in  the  leg  of  the  bird,  we  may  observe  the  femur,  below  it 
the  tibia,  but  in  place  of  the  tarsus  and  metatarsus,  there  is 
only  a  single  bone  to  which  the  phalanges  are  attached. 
Here  is  a  gross  dissimilarity  which  strongly  militates  against 
the  unity  of  structure.  If  we  turn,  however,  to  the  develop- 
ment of  the  bird  in  the  egg,  the  dissimilarity  is  dissipated 
at  once.  For  we  find  in  the  f  cetal  bird,  first  the  femur,  then 
the  tibia,  below  it  two  bones  to  constitute  the  tarsus,  and 
below  these  two  short,  thick  bones,  and  parallel  with  each 
other,  are  three  or  four  long,  slender  metatarsal  bones  to 
which  are  appended  the  phalanges.  The  upper  tarsal  bone 
subsequently  coalesces  with  the  femur,  the  lower  with  the 
tibia,  the  metatarsal  coalesce  with  each  other  to  form  one, 
and  thus  is  the  leg,  as  well  as  the  wing  of  the  bird,  shown  to 
be  constructed  from  the  same  fundamental  form.  "In 
short,  the  history  of  development,"  as  Oscar  Schmidt  ob- 
serves, "which  describes  the  gradual  formation  of  the  organ- 
ism, is  at  every  step  a  beacon  to  comparative  anatomy." 

While  we  are  considering  the  lower  extremity,  I  may  call 
your  attention  to  the  fact  that  Carl  Vogt  has  shown  the 
foot  of  the  gorilla  to  be  more  anthopoid  than  that  of  any 
other  ape,  and  the  foot  of  the  negro  more  ape-like  than  that 
of  the  white  man.  The  bones  of  the  tarsus  in  the  gorilla 
exactly  resemble  those  in  the  negro ;  the  ape  has  the  same 
broad,  flat,  low  heel ;  the  large  toe  is  thicker  and  longer 
than  in  the  other  apes,  but  the  toes,  on  the  whole,  are 


THE  RUDIMENTARY  ORGANS.  77 

longer,  more  moveable  and  the  thumb  more  opposable. 
"The  posterior  limbs  of  the  gorilla,"  says  Huxley,  "terminate 
in  a  real  foot,  with  a  moveable  great  toe.  It  is  a  prehensile 
foot,  if  you  like,  but  no  hand,  a  foot  which  differs  from  that 
of  man,  not  in  any  fundamental  character,  but  in  mere  pro- 
portions, in  the  degree  of  mobility  and  in  the  secondary 
arrangement  of  its  parts." 

The    Rudimentary    Organs. 

Comparative  anatomy,  again,  furnishes  a  lucid  interpreta- 
tion of  the  significance  of  those  obscure  structures  in  the 
body  known  as  the  rudimentary  organs.  As  animals  be- 
came subjected  to  different  external  conditions  in  the  vary- 
ing history  of  the  earth,  new  organs  originated  from  time  to 
time,  or  what  was  most  frequent,  simple  structures  became 
more  and  more  perfected  until  entirely  different  varieties 
had  been  formed.  These  peculiarities  of  structure  were,  of 
course,  continually  transmitted  by  heredity.  But  as  the 
surrounding  conditions  continued  to  change,  the  adjustment 
or  adaptation  to  these  conditions,  necessary  to  secure  the  ex- 
istence and  propagation  of  the  species,  would  lead  to  the 
gradual  sacrifice  or  reduction  of  organs,  or  parts,  until  at 
last  they  would  be  present  in  a  body,  if  present  at  all,  in  at- 
rophied or  merely  rudimentary  form.  Such  rudiments  or 
traces  of  structures  which  continue  to  be  highly  developed 
among  lower  animals,  everywhere  abound  in  the  body  of 
man.  Indeed,  no  system  of  organs  in  the  body  of  man  is 
free  from  structures  thus  reduced  by  disuse,  and  like  ex- 
amples are  encountered  throughout  the  animal  and  vegetable 
kingdom. 

The  wings  of  animals  which  have  lost  the  power  of  flight 
are  examples  of  rudimentary  organs.  In  the  ostrich,  the 
emeu  and  cassowary,  the  legs  have  gradually  become  enorm- 
ously developed,  because  flight  was  unnecessary  on  account 


78  BONE  RUDIMENTS. 

of  the  absence  of  beasts  of  prey,  consequently  the  wings 
have  become  gradually  reduced  by  disuse. 

The  atrophied  lung  of  serpents  and  lizards  and  the  aborted 
ovary  of  birds  are  also  examples  of  rudimentary  organs. 
The  slender  length  of  the  body  of  the  snake  leaving  no  room 
for  the  pair  of  lungs  to  which  it  is  entitled,  the  one  under- 
goes atrophy  and  the  other  compensates  for  its  loss  by  its 
elongation.  So  the  right  ovary  is  aborted  in  birds  as  a 
superfluous  encumbrance  in  weight.  Teeth  which  never  cut 
through  to  appear,  as  those  in  the  embryo  of  the  whale  and 
ox,  eyes  which  do  not  see,  as  those  in  moles  and  under- 
ground mice,  cave  beetles  and  crabs,  etc.,  the  hind  leg  bones 
of  whales  and  boas,  which  never  develop,  are  additional  ex- 
amples of  rudimentary  organs. 

Bone   Rudiments. 

When  we  come  to  the  body  of  man,  we  encounter,  as  has 
been  said,  rudimentary  structures  in  every  system  of  organs. 
Perhaps  the  most  striking  example  in  the  bony  skeleton  is 
the  coccyx,  the  rudimentary  tail.  The  individual  bones  of 
the  coccyx  are  each  but  traces  of  whole  vertebree  as  they 
are  composed  of  the  defective  central  bone,  without  any  of 
the  characteristic  processes.  Occasional  monstrosities  ex- 
hibit the  coccyx  of  unusual  length.  "It  is  in  monstrosities," 
it  has  been  said,  "that  Nature  reveals  her  secrets."  A 
distinct  rudimentary  structure  is  sometimes  found  at 
the  lower  extremity  of  the  humerus.  It  is  a  small 
hook-like  process  of  bone  projecting  downwards  towards 
the  inner  condyle,  with  which  it  is  sometimes  connected 
by  a  band  of  fibrous  ligament.  It  corresponds  to  the 
supra-condyloid  foramen  of  feline  animals,  transmitting 
the  brachial  artery  and  often  the  median  nerve  and 
protecting  them  from  compression  during  the  contrac- 
tion of  muscles  in  seizing  and  holding  prey.    This  rudi- 


MUSCLE  RUDIMENTS.  79 

mentary  process  of  bone,  though  present  in  only  about  one 
per  cent.,  of  recent  skeletons,  is  much  more  commonly  met 
in  ancient  specimens  ;  thus  Dupont  found  thirty  per  cent. 
of  humeri  perforated  in  the  caves  of  the  valley  of  the 
Lesse,  belonging  to  the  Eeindeer  period. 

Muscle   Rudiments. 

The  muscular  system  is  peculiarly  rich  in  rudimentary 
structures.  Remnants  of  the  panniculus  camosus,  the  great 
surface  muscle  of  the  horse,  are  met  in  the  platysma 
myoides,  the  surface  muscle  of  the  neck,  and  in  fasciculi  in 
the  axillae  and  near  the  scapulae,  as  also  in  the  superficial 
muscles  of  the  scalp  so  markedly  developed  still  in  some 
people.  The  extrinsic  muscles  of  the  ear  are  typical  rudi- 
mentary structures.  These  muscles  are  highly  developed 
among  wild  animals  and  give  the  external  ear  its  quick 
motion  in  different  directions  to  catch  the  faintest  sounds. 
As  the  animals  became  domesticated  and  the  danger  less- 
ened, the  muscles  gradually  atrophied.  Many  dogs  and 
rabbits,  the  latter  the  most  timid  of  all  animals,  have  thus 
in  security  lost  the  power  to  "prick  up"  the  ears,  which  have 
become  in  time  long  and  loose  appendages.  Though  careful 
dissection  will  reveal  traces  of  these  muscles  in  man,  their 
power  is  lost  except  in  rare  cases.  The  intrinsic  muscles  of 
the  ear  have  become  more  rudimentary  still,  and  the  ability 
to  move  parts  of  the  auricle  upon  each  other  is  entirely  lost. 
The  rudimentary  muscles  about  the  coccyx,  the  relics  of  the 
powerful  muscles  of  the  tail  in  the  lower  animals,  are 
worthy  of  mention  in  concluding  the  examples  from  the 
muscular  system. 

Rudiments  from  the  Digestive  System. 

The  digestive  system  furnishes  two  notable  rudimentary 
structures.     One  is  the  wisdom  tooth.     On  account  of  the 


80  RUDIMENTARY  ORGANS. 

softer  character  of  the  food  in  civilized  life,  less  mastication 
is  required,  consequently  the  length  of  the  jaws  is  being  re- 
duced and  room  is  scarcely  afforded  for  all  the  last  molar 
teeth.  The  very  last  is  the  last  to  appear  and  the  first  to 
fall.  It  has  now  but  two  fangs,  whereas  in  ancient  skeletons 
it  possesses  three,  the  number  normal  to  molar  teeth.  It  is 
the  most  caducous  of  all  teeth  and  is  slowly  becoming  rudi- 
mentary. The  absence  and  not  the  presence  therefore  of 
the  last  molar  tooth  will  have  to  be  regarded  as  the  sign  of 
"wisdom."  The  other  example  from  the  digestive  system  is 
the  vermiform  appendix.  The  preparation  of  the  food  has 
become  such  a  science  as  to  limit  the  period  of  digestion  in 
the  body.  It  might,  indeed,  be  said  that  the  food  is  largely 
digested  by  the  cuisine  before  its  ingestion  into  the  body. 
Consequently  much  of  the  capacity  of  the  alimentary  canal 
has  .become  superfluous;  The  head  of  the  large  intestine, 
which  forms  almost  an  additional  stomach  in  the  gramnivora, 
and  is  three  times  the  length  of  the  whole  body  in  the  mar- 
supial koala,  is  very  much  reduced  in  the  carnivora,  whose 
food  contains  but  little  indigestible  matter,  and  is  greatly 
reduced  in  the  omnivora,  as  in  man.  The  vermiform 
appendix  is  the  shriveled  remnant  of  the  great  coecal  recep- 
taculum  of  the  lower  animals.  In  the  orang-outang  it  is 
still  a  long  convoluted  tube,  but  in  man  it  is  reduced  to  the 
size  of  a  quill  three  or  four  inches  in  length,  mostly  blocked 
with  mucus.    It  is  often  entirely  absent. 

Other   Rudiments. 

From  the  nervous  system  the  most  striking  rudimentary 
organ  is  the  filum  terminale  of  the  spinal  cord,  the  continu- 
ation downwards  of  the  envelops  of  the  cord  to  the  extremity 
of  the  coccyx,  the  relic  of  the  prolonged  cord  of  the  lower 
animals. 

The  short  hairs  over  the  whole  surface  of  the  body  and 


RUDIMENTARY   ORGANS.  81 

tlio  lanugo  or  wool  of  the  foetus  over  the  whole  surface,  ex- 
cept the  palms  of  the  hands  and  soles  of  the  feet,  where  it  is 
absent  in  most  of  the  lower  animals,  are  clearly  rudiments 
of  the  universal  hairy  coat  of  these  animals.  Occasionally 
a  'reversion'  is  encountered  in  the  birth  of  an  Esau  with  a 
hairy  coat. 

The  eye  and  the  ear  each  possess  a  rudimentary  structure 
of  curious  interest.  At  the  nasal  angle  of  each  eye  is  a 
small,  semi-lunar  fold  of  mucous  membrane,  the  plica  semi- 
lunaris, which  is  clearly  a  rudiment  of  the  nictitating  mem- 
brane, the  third  or  inner  eye-lid  in  mammals,  birds  and  rep- 
tiles. In  these  animals  the  nictitating  membrane  is  fur- 
nished with  a  muscle  to  secure  its  extension  across  the  entire 
globe  of  the  eye,  in  protection  of  the  retina  from  too  great 
light.  Sufficient  protection  is  afforded  in  man  by  the 
more  highly  developed  lashes,  lids  and  iris,  and  the  nictitat- 
ing membrane  has  become  reduced  to  an  insignificant  frag- 
ment. 

At  a  point  about  at  the  junction  of  the  upper  and  middle 
third  of  the  helix  of  the  external  ear  there  may  be  commonly 
seen  a  small  blunt  point  projecting  towards  the  antihelix. 
Mr.  Darwin  had  his  attention  directed  to  this  projection  by 
a  celebrated  English  sculptor,  and  he  docs  not  hesitate  to 
interpret  it  as  the  "point  of  the  ear"  turned  in,  the  vestige  of 
formerly  pointed  ears  in  the  primal  races  of  man.  "In 
many  monkeys,"  he  says,  "which  do  not  stand  as  high  in  the 
order  as  baboons  and  some  species  of  macacus,  the  upper 
portion  of  the  ear  is  slightly  pointed  and  the  margin  is  not 
at  all  folded  inwards ;  but  if  the  margin  were  to  be  thus 
folded,  a  slight  point  would  necessarily  project  inward  and 
probably  a  little  outward."  Whether  this  point  be  so  re- 
garded or  not,  it  is  pretty  generally  accepted  that  the  whole 
external  ear,  the  auricle,  having  become  an  immobile  shell, 
hence  useless,  should  be  considered  as  a  true  rudimentary 


82  EXPLANATIONS  OF  RUDIMENTS. 

structure.  When  all  its  involutions  are  filled  with  wax  so 
as  to  make  its  internal  aspect  a  plane  surface,  or  when  it  is 
entirely  removed,  as  by  accident  or  operation,  the  sense  of 
hearing  is  in  no  way  impaired. 

Explanations  of  Rudiments. 

The  explanations  offered  to  account  for  these  rudimentary 
structures  in  man  on  any  other  theory  than  that  of  inherit- 
ance from  a  common  type  and  reduction  by  disuse,  are  as 
irrational  and  ridiculous  as  those  to  account  for  the  existence 
of  fossils,  and  serve  simply  to  show  "the  embarrassment  and 
distress  which  their  presence  has  occasioned."  It  was 
claimed,  for  instance,  that  they  were  furnished  to  animals 
having  no  use  for  them  to  sustain  the  general  plan  of  crea- 
tion, or  for  the  sake  of  symmetry,  "just  as  doctors  in  the 
army  and  navy  are  made  to  wear  small  and  useless  swords 
to  be  in  keeping  with  the  officers  of  the  line."  But  the  en- 
dowment of  the  highest  animals  in  the  scale  with  organs 
which  are  not  only  useless,  but  sometimes  absolutely  injuri- 
ous (deaths  have  occurred  from  impaction  of  the  vermiform 
appendix  with  fruit-seeds  and  stones),  would  notseem  to  be 
in  keeping  with  a  very  high  design  or  order  of  creation. 
This  explanation,  therefore,  is  sufficiently  ridiculous,  but 
another  offered  by  an  eminent  physiologist  reaches  the  very 
climax  of  absurdity.  It  is  claimed  for  these  rudimentary 
organs  that  they  serve  to  excrete  matter  that  is  useless  or 
injurious  to  the  system  ! 

Mr.  Lyell  says,  in  his  Principles  of  Geology,  that  he  asked 
Lamarck  in  the  year  1867,  when  he  was  in  his  84th  year,  by 
what  facts  and  reasonings  he  had  been  led  to  entertain  his 
views,  "and  he  told  me  that  he  owed  his  convictions  to  the 
lectures  of  Geoffroy  St.  Hilaire,  to  which  he  had  listened  in 
the  early  part  of  this  century  at  Paris.  That  great  zoologist, 
he  said,  never  lost  an  opportunity,  when  he  spoke  of  the 


EXPLANATION  OF  RUDIMENTS.  83 

rudimentary  organs  found  in  so  many  animals,  of  pointing 
out  their  bearing  on  the  theory  of  transmutation.  Accord- 
ing to  him,  they  were  clearly  the  relics  of  parts  which  had 
been  serviceable  in  some  remote  ancestor  and  had  been  re- 
duced in  size  by  disuse,  and  he  rejected  the  idea  as  puerile 
that  useless  organs  had  been  created  for  the  sake  of 
uniformity  of  plan."  In  truth,  there  is  absolutely  no  scien- 
tific explanation  for  these  rudimentary  structures  other 
than  that  of  inheritance  from  a  common  ancestral  form  and 
gradual  suppression  by  disuse,  because  of  subjection  to  con- 
ditions, in  which  they  are  no  longer  of  avail. 

We  have  dwelt  at  length  upon  the  most  marked  examples 
of  these  strange  traces,  without  having  by  any  means  ex- 
hausted the  list,  because  of  their  peculiar  significance  in  the 
interpretation  of  the  development  of  life.  What  the  germ 
is  to  the  future,  is  the  relic  to  the  past.  Eudiments  are  like 
the  blocks  of  ancient  temples  incorporated  into  the  modern 
edifices  which  have  taken  their  place.  But  they  differ  from 
them  in  being  of  no  use.  They  are  fragments  of  the  crumb- 
ling columns  of  antiquity. 

No  testimony  is  more  convincing  of  man  s  place  in  nature 
than  that  so  speakingly  furnished  by  these  rudimentary 
structures.  For,  as  Mr.  Darwin  has  eloquently  expressed 
it,  (I  take  the  liberty  to  interpolate  a  single  line),  by 
them  we  see  that  man  with  all  his  noble  qualities,  with 
sympathy  that  feels  for  the  most  abject,  with  benevo- 
lence which  extends  not  only  to  his  fellow-man,  but  to  the 
humblest  living  thing  on  earth,  with  an  imagination  that 
outrivals  and  mocks  for  expression  his  marvelous  gift  of 
speech,  with  a  God-like  intellect  which  has  penetrated  to  the 
structure  and  movements  of  the  heavenly  bodies— man, 
with  all  these  exalted  powers — still  bears  indelible,  in  every 
organ  of  his  frame,  the  stamp  of  his  lowly  birth. 


84  THE  EVOLUTION   OF  FORMS  OF  LIFE. 


LECTURE   V. 


THE  EVOLUTION  OF  FOEMS  OF  LIFE. 

CONTENTS. 

The  Law  of  Inheritability — Transmission  of  Acquired  Defects — Homo- 
chronous  Transmission — Atavism — The  Physics  of  Reproduction- 
Adaptation  to  External  Conditions — Difficulty  of  Classification — Arti- 
ficial Selection — The  Struggle  for  Existence — Natural  Selection — 
Protective  Colors — Warning  Colors — Sexual  Selection — Complications 
in  Natural  Selection — Preservation  of  the  Individual  and  of  the  Race 
— General  Summary. 

In  concluding  our  consideration  of  the  evolution  of  life 
we  have  to-day  to  study  the  forces  or  laws  which  preserve, 
perfect  and  diversify  its  forms.  I  desire  to  state,  at  the 
start,  that  though  I  shall  quote  from  very  many  authorities, 
I  am  indebted  for  many  of  the  facts  which  I  shall  present 
you  to-day,  to  the  publications  of  Darwin,  and  for  most  of 
them  to  the  Naturliche  jSchopfung ,  s-geschichte  (History  of 
Creation)  of  Haeckel,  a  work  so  complete  and  comprehen- 
sive, as  to  have  elicited  from  Mr.  Darwin  the  statement,  in 
the  preface  to  his  Descent  of  Man,  "If  this  work  had  appeared 
before  my  essay  had  been  written,  I  should  probably  never 
have  completed  it."  I  am  led  to  present  you  this  aspect  of 
,the  subject  simply  to  complete  the  evidence  for  evolution 
with  its  most  important  proof. 

The  overshadowing  law  which  insures  the  perpetuity 
of  form  is  that  of 

Inheritability. 

That  "like  begets  like"  is  a  proverb  in  every  language. 
The  law  of  inheritance  is  so  universally  recognized  and 
acknowledged  as  to  be  accepted  as  a  matter  of  course.    It  is 


THE  PERPETUATION   OF  FORM.  85 

the  breach  and  not  the  observance  of  the  law  which  makes 
it  the  subject  of  comment.  The  birth  of  a  child  with  webbed 
or  supernumerary  fingers  or  toes  calls  up  the  history  of  the 
remote  ancestry  in  its  explanation.  The  cohesion  of  the 
family,  which  is  the  safeguard  of  the  state  and  nation,  rests 
upon  the  acceptance  of  the  principle  of  heredity.  The  law 
of  heredity,  if  we  may  be  allowed  to  coin  the  word,  secures 
to  the  offspring  not  only  the  reproduction  of  the  general 
form  of  the  parent,  but  also  the  exact  repetition  of  every 
physical  and  mental  feature,  characteristic  of  the  parent. 
There  were  families  in  Rome  which  received  from  the  shape 
of  the  nose  or  lips  the  titles  of  the  nasones,  labeones,  buccones, 
etc.  Aquiline  noses  are  still  transmitted  among  the  posterity 
of  the  Bourbons.  The  Hapsburg  (Austria)  lip  is  a  pecu- 
liarity worthy  of  mention  in  this  connection.  The  Prussian 
kings  are  noted  for  their  stature.  Obesity,  color,  tempera- 
ment, longevity,  are  all  strictly  transmitted  by  heredity. 
Vices  of  conformation,  deformities,  diseases,  are  alike  re- 
produced in  the  offspring ;  moles,  freckles,  tumors,  appear 
in  the  offspring  in  exactly  the  same  spots  as  in  the  parents. 
The  ancestral  history  is  carefully  examined  by  the  physician 
in  establishing  his  diagnosis  of  disease.  Affections  of  the 
respiratory  organs,  e.  g.,  tuberculosis;  of  the  glands,  scrofula; 
of  the  nervous  system,  epilepsy,  are  especially  liable  to  be 
propagated  in  the  offspring.  Traits  of  mind  are  transmitted 
with  equal  fidelity.  The  family  of  Miltiades  furnished 
heroes,  of  Pericles  politicians.  In  the  family  of  Bach  there 
were  no  less  than  twenty-two  musicians.  For  a  generation 
the  name  of  Graefe  was  venerated  in  medicine  in  Berlin, 
and  in  Boston  generations  of  Warrens  have  been  distinguished 
physicians.  So  for  generations  the  Eothschilds  have 
been  renowned  for  a  special  talent  in  the  acquisition 
of  wealth.  The  horrible  cruelties  of  the  Borgias  are 
counterbalanced  in  some  degree,   to  the  credit  of  Italy, 


§6  TRANSMISSION  OF  ACQUIRED  DEFECTS. 

by  the  refinement  and  culture  of  the  Florentine  Medici. 
It  is  hardly  necessary  to  state  that  the  law  of  transmission 
holds  with  equal  force  throughout  the  animal  and  vegetable 
kingdoms.  Albinoes,  i.  e.,  animals  devoid  of  color,  have 
been  propagated  as  a  separate  species  among  rabbits  and 
mice,  as  well  as  among  men.  Paraguay  is  noted  for  a  special 
race  of  hornless  oxen,  bred  from  a  bull  born  in  1770  without 
horns.  The  harmless  character  of  the  animal  made  it  the 
subject  of  special  selection  in  breeding,  until  a  whole  race 
was  thus  obtained.  The  well-known  case  of  the  otter  sheep 
in  our  own  country  is  a  good  illustration  of  the  force  of 
heredity.  A  Massachusetts  farmer  discovered  one  day 
among  his  flock  an  individual  sheep  "with  a  surprisingly 
long  body  and  short  and  crooked  legs."  It  occurred  to  the 
farmer  that  this  development  would  be  advantageous  in 
rendering  leaping  impossible  and  thus  checking  depreda- 
tions upon  a  neighbor's  property.  He  forthwith  bred  from 
this  individual  with  the  desired  result,  and  his  neighbors 
following  his  example,  the  sheep  of  Massachusetts  soon 
became  noted  for  their  staid  decorum  and  profound  respect 
for  others'  lands. 

Transmission  of  Acquired  Defects. 

Even  acquired  defects  are  sometimes  transmitted.  Thus 
Brown-Sequard  produced  epilepsy  in  some  guinea-pigs  by 
injuring  certain  parts  of  their  brains,  and  this  artifically- 
induced  epilepsy  appeared  spontaneously  in  all  the  offspring 
of  the  diseased  animals.  Haeckel  states  that  a  race  of 
tailless  dogs  was  once  propagated  by  persistently  cutting  off 
the  tails  of  both  sexes  of  the  dog  for  several  generations. 
The  same  author  narrates  that  a  few  years  ago,  on  an  estate 
near  Jena,  a  bull  had  his  tail  wrenched  off  by  the  careless 
slamming  of  a  stable  door,  and  "all  the  calves  begotten  of 
this  bull  were  born  without  a  tail." 


ATAVISM.  87 

Ilomochronous  Transmission. 

So  strong  is  the  force  of  heredity,  that  diseases  and  defects 
are  not  only  transmitted,  but  they  are  transmitted  homo- 
chronously,  that  is,  to  appear  in  the  offspring  at  the  same 
age  in  which  they  were  manifested  in  the  parents.  Diseases 
of  the  lungs,  liver  and  brain  occur  in  the  child  at  the  same 
period  of  life  as  in  the  parent  before  it. 

Atavism. 

But  under  the  laws  of  heredity  the  offspring  may  resemble 
not  so  much  its  parents  as  its  grandparents,  or  ancestry 
even  more  remote.  This  is  the  phenomenon  of  atavism,  as 
it  is  called.  How  many  peculiarities  or  eccentricities  might 
we  not  be  able  to  explain,  if  we  could  only  sum  up  all  the 
atoms  of  being  that  have  come  down  to  us  from  the  bodies 
of  our  ancestors  in  regular  line.  Oliver  Wendell  Holmes 
bases  several  of  the  best  characters  in  his  novels  upon  the 
influence  of  heredity  as  far  back  as  can  be  traced.  We  ob- 
serve this  phenomenon  of  atavism  in  the  everyday  history 
of  some  of  the  lower  animals  and  plants.  The  planarian 
worms,  for  instance,  as  well  as  the  ferns  and  mosses,  beget 
forms  entirely  different  from  themselves,  and  it  is  only  in 
the  offspring  of  these  different  forms  that  the  image  of  the 
first  parents  is  reproduced.  This  alternation  of  generation 
was  first  remarked  by  the  poet  Chamisso,  during  his  voyage 
around  the  world  in  1819,  in  the  case  of  the  salpae,  small 
transparent  structures,  which  float  like  particles  of  glass  on 
the  surface  of  the  sea.  In  studying  the  habits  and  life 
history  of  these  animals,  Chamisso  observed  that  the  parent 
form,  which  has  an  eye  of  crescent  or  horseshoe-shape,  pro- 
duces offspring  with  cone-shaped  eyes,  but  in  the  offspring  of 
the  offspring,  the  grand-children,  so  to  speak,  the  original 
eye  of  horseshoe-shape  reappears.     Among  other  animals  a 


88  THE  PHYSICS  OF  HEPKODUCTION. 

still  greater  number  of  alternations  manifests.  The  sea 
buoys,  for  instance,  skip  over  three  generations,  and  plant 
lice  ten  or  twelve,  before  the  original  form  reappears. 
£'trange  as  this  alternation  of  form  seems  at  first,  it  is  really 
not  more  strange  than  the  different  phases  of  development 
at  different  ages  in  the  life  of  every  animal  and  plant,  and 
it  is  in  this  light,  therefore,  of  successive  phases  of  develop- 
ment, that  we  may  regard  these  various  alternative  forms. 
We  shall  have  later  explanation  for  the  fact  so  often  ob- 
served in  man,  and  even  more  frequently  among  the  lower 
animals,  that  individuals  are  occasionally  born  which  repro- 
duce in  form  and  character  some  ancient  ancestor,  or  a 
type  so  remote  as  to  have  become  almost  extinct.  Horses, 
for  instance,  occasionally  show  such  reversions  to  the  zebra 
or  quagga  in  stripes  across  the  shoulders  or  along  the  spinal 
column,  and  puppies  and  heifers  are  sometimes  born  which 
revert  in  form  to  types  long  extinct. 

Thus,  then,  is  evidenced  the  force  of  heredity.  It  appears 
at  first  a  great  and  incomprehensible  mystery,  "the  mystery 
of  mysteries"  once  it  was  called.  The  exact  reproduction 
of  form  and  feature,  vice  and  virtue,  disease  and  deformity 
from  structures — the  sperm  and  germ  cells — beyond  the 
power  of  vision  with  the  naked  eye,  would  seem  a  problem 
beyond  the  limits  of  human  analysis.  "If  the  naturalist," 
said  Virchow,  "cared  to  follow  the  custom  of  historians  and 
metaphysicians  in  clothing  phenomena,  which  are  in  their 
way  unique,  with  the  hollow  pomp  of  ponderous  and  sound- 
ing words,  here  would  be  his  opportunity." 

The  Physics  of  Reproduction. 

But  a  close  observation  of  the  method  of  reproduction 
among  the  lowest  forms  of  life  reveals  an  entirely  material 
process,  cognizable  to  the  human  mind.  That  is,  it  is  not 
necessary  in    its  comprehension  to  take  refuge  under  a 


THE  PHYSICS  OF  EEPPODTJCTIOxT.  89 

"miracle."  The  process  of  reproduction  is  a  growth  beyond 
the  natural  limit  of  size.  In  the  amoeba,  for  instance,  a 
simple,  irregular,  gelatinous,  mass  of  protoplasm,  reproduc- 
tion is  effected  by  the  separation  from  the  parent  of  a  pro- 
truded particle  of  protoplasm,  containing  atoms  or  molecules 
of  structure  exactly  like  the  main  mass.  The  reproduction 
or  proliferation  of  cells  in  a  more  complex  body  is  the  same 
process  of  separation,  mostly  by  division,  of  part  of  the 
protoplasm  from  the  rest.  In  the  highest  animal,  man,  the 
offspring,  the  new  body,  is  developed  from  cells  originally 
derived  from  each  parent.  The  ovum  is  as  much  a  part  of 
the  maternal,  and  the  spermatozoids  of  the  paternal,  organ- 
ism, as  the  eye  or  any  other  organ,  and  the  entire  body  of 
the  child  is  only  an  aggregate  of  cells  multiplied  and 
differentiated  from  the  simple  cells  of  the  ovum  and 
spermatozoid.  The  child  must  resemble  its  parent  because 
it  is  of  its  parent  a  part.  It  must  resemble  it  just  as  a  piece 
of  coal  detached  from  a  mass  must  resemble  the  original 
mass.  "The  child,  strictly  speaking,  does  not  grow  into  the 
man,  but  includes  germs,  derived  from  its  parents,  which 
slowly  and  successively  become  developed  and  form  the 
man."  Some  of  these  germs,  however,  may  have  descended 
from  an  ancestor  more  remote,  and  lain  dormant  in  the 
immediate  parent,  to  become  developed,  under  conditions, 
inexplicable  as  yet,  only  in  the  child.  The  phenomenon  of 
reversion,  or  atavism,  as  it  is  technically  called,  thus  ceases 
to  be  mysterious.  We  are  informed  by  those  who  have 
made  the  size  of  molecules  or  ultimate  atoms  the  subject  of 
special  study,  that  the  minute  ovum  dl0~i2o  °f  an  ^oh 
diameter),  may  contain  as  many  as  five  thousand  billions 
gemmules.  Mr.  Sorby  states  that  the  number  of  mole- 
cules in  the  germinal  vesicle  (granting  that  this  con- 
stituent of  the  ovum  is  the  only  essential  structure)  of  the 
mammalian  ovum,  is  such  that  if  one  molecule  were  to  be 

8 


90  ADAPTATION  TO  CONDITIONS. 

lost  in  every  second  of  time,  the  whole  would  not  be  ex- 
hausted in  seventeen  years.  Surely  here  are  sufficient 
particles,  as  Mr.  Thompson  puts  it,  "for  all  the  require- 
ments of  the  most  exacting  biologist."  In  the  reproduction 
of  man  the  gemmules  from  both  parents  blend  to  produce 
the  child.  The  question  then  is  not;  does  the  child  resem- 
ble its  parent;  but  which  parent  does  it  resemble  most? 
Said  Goethe : 

"Von  Vater  habc  ich  die  Statur,  des  Lebens  ernstes  Fiihren; 
Von  Miitterchen  die  Frohnatur  und  Lust  zu  fabuliren." 

(From  my  father  is  my  stature  and  earnestness  of  mien; 
From  my  mother  is  my  joyousnessand  love  of  romance  keen.) 

The  force  or  law,  therefore,  which  secures  the  perpetuation 
of  forms  of  life  is  the  force  or  law  of  heredity. 

We  take  up  now  the  force  or  law  which  produces  their 
variation.     This  force  is  that  of 

Adaptation  or  Adjustment 

to  the  surrounding  conditions,  as  effected  m  slight  degree, 
comparatively  speaking,  by  artificial,  and  in  high  degree, 
through  the  inconceivable  ages  of  the  past,  by  natural  selec« 
tion. 

The  proofs  of  the  evolution  of  forms  of  life,  and  their 
variation  from  each  other,  based  upon  the  action  of  artificial 
and  natural  selection,  are  the  most  convincing  of  all.  From 
an  historical  standpoint,  they  are  also  the  most  interesting, 
as  having  been  the  means  of  securing  the  adoption  of  the 
theory  of  descent.  If  we  had  observed  the  proper  chrono- 
logical order  in  exhibiting  the  facts  bearing  upon  this  sub- 
ject, according  to  the  period  of  their  disclosure,  we  should 
have  first  discussed  the  action  of  artificial  and  natural  selec- 
tion. Lamarck  had  propounded  the  theory  of  evolution, 
it  is  true,  but  his  views  were  regarded  as  visionary,  until 


CHARLES   ROBERT   DARWIN.  91 

proofs  were  advanced  by  a  later  observer,  establishing  it 
almost  beyond  dispute.  It  is  almost  unnecessary  to  state 
at  this  stage  of  general  information  on  this  subject,  that  the 
name  of  this  later  observer  is 

Charles  Robert  Darwin. 

The  conclusions  reached  by  the  investigations  of  Mr.  Darwin 
mark  an  epoch  in  biology  as  distinct  as  those  of  Galileo  in 
astronomy,  or  of  Newton  in  physics.  Like  these  most  dis- 
tinguished men,  Darwin  disclosed  not  a  single  discovery  or 
isolated  fact,  but  a  great  underlying  principle,  more  far- 
reaching,  however,  in  its  conclusions  and  influential  in  its 
effects  in  relation  to  the  position  and  prospects  of  mankind, 
than  any  preceding  revelation  in  the  history  of  science.  The 
train  of  thought  and  study  which  led  to  these  conclusions, 
he  has  himself  described  in  a  letter  to  Haeckel,  October  8, 
1364,  from  which  is  the  following  extract :  "But  for  some 
years  I  could  not  conceive  how  each  form  became  so  excel- 
lently adapted  to  its  habits  of  life.  I  then  began  systemati- 
cally to  study  domestic  productions,  and  after  a  time  saw 
clearly  that  man's  selective  power  was  the  most  important 
agent.  I  was  prepared,  from  having  studied  the  habits  of 
animals,  to  appreciate  the  struggle  for  existence,  and  my 
work  in  geology  gave  me  some  idea  of  the  lapse  of  past  time. 
Therefore,  when  I  happened  to  read  'Malthus  on  Popula- 
tion,' the  idea  of  natural  selection  flashed  upon  me." 

"Some  few,  whose  lamp  shone  brighter  have  been  led 
From  cause  to  cause  to  nature's  secret  head 
And  found  that  one  fixed  principle  must  be."         Dryden. 

Difficulty  of  Classification. 

Darwin  had  hitherto  always  entertained  the  view,  in  com- 
mon with  all  naturalists,  that  all  species  of  animals  were 
separately  and  independently  created,  and  were  consequently 


92  ARTIFICIAL  SELECTION. 

immutable  in  form.  But,  to  say  nothing  of  any  other  objec- 
tion to  this  view,  there  remained  always  the  insurmountable 
difficulty  and  disagreement  as  to  classification.  If  species 
were  separate  and  immutable,  classification  should  have 
been  simple  and  easy.  Special  features  should  have  readily 
marked  special  varieties.  The  truth  was,  however,  that  no 
two  zoologists  or  botanists  agreed  in  their  divisions.  We 
might  take  as  an  example  one  of  the  commonest  European 
plants,  the  Hieracium.  Some  300  species  of  this  plant  were 
recognized  in  Germany,  but  the  botanist  Fries  only  ad- 
mitted 10G,  Koch  but  52,  and  others  only  20.  The  same 
difference  is  met  with  in  the  case  of  the  brambles.  One 
botanist  claims  100  different  species,  another  50,  and  a  third 
groups  them  all  into  5  or  6.  In  zoology  there  is  as  much 
disagreement.  Thus  Bechstein  distinguishes  3G7  species  of 
German  birds,  Keichenbach  379,  Mayer  and  Wolff  406,  while 
Brehm  is  able  to  find  special  characteristics  for  no  less  than 
900  species.  From  such  gross  disparities  in  classification,  it 
is  plain  to  see  that  the  specific  differences  assumed  must 
have  been  largely  arbitrary.  On  the  theory  of  adjustment 
or  adaptation  to  different  surrounding  conditions,  the 
varieties  of  species  are  easily  understood.  The  habits  of  life 
determine  the  species,  and  as  these  habits  must  change  with 
the  continual  changes  of  the  external  conditions,  the  muta- 
tions of  form,  "the  species,"  are  limitless. 

Artificial  Selection. 

It  was  the  radical  changes  that  man  was  able  to  effect  in 
the  domesticated  animals  and  plants  which  gave  Mr.  Darwin 
the  clue  through  the  labyrinth  of  the  different  species.  It 
might  be  said  that  we  make  new  species  ourselves  every  day 
in  the  cultivation,  i.  e.  domestication,  of  wild  animals  and 
plants.  We  cripple  the  wings  of  ducks  and  fowls,  and  re- 
duce to  rudiments  the  car  muscles  of  rabbits  and  dogs,  by 


ARTIFICIAL  SELECTION.  93 

simply  removing  them  to  places  of  security.  Captivity 
nearly  entirely  arrests  reproduction  in  elephants,  bears  and 
monkeys,  or  changes  its  whole  character.  The  common  ring 
snake,  for  instance,  lays  eggs  which  are  not  hatched  out  for 
three  weeks,  but  if  the  snake  be  confined  in  a  cage  it  does 
not  lay  eggs  at  all,  but  retains  them  in  the  body  until 
development  is  complete.  The  very  radical  change  from  an 
oviparous  to  a  viviparous  animal  is  thus  artificially  produced. 
A  gardner  can  produce  any  colored  flower  almost  at  will, 
alter  the  leaf  or  stem,  dwarf  or  develop  any  peculiarity,  by 
changing  the  external  conditions. 

Perhaps  the  pigeon-breeders  make  the  most  abundant 
and  most  striking  experiments  in  the  modification  of  form. 
The  art  of  piegon-breeding  is  said  to  be  very  ancient.  The 
Egyptians  engaged  in  it  3000  years  before  Christ,  and  the 
Romans  m  the  days  of  the  Emperors  had  already  commenced 
to  record  the  pedigree  of  certain  species,  as  the  Arabs  that 
of  their  horses,  or  aristocrats  among  men  that  of  themselves. 
The  court  of  Abder  Khan  in  Asia,  possessed  in  the  year 
1600  more  than  20,000  pigeons.  Inter-breeding  and  cross- 
breeding, subjection  to  different  kinds  of  food,  to  different 
climates,  to  the  multitudious  differences  embraced  under 
the  general  term  surrounding  conditions,  have,  in  the  course 
of  centuries,  produced  more  than  150  varieties  of  pigeons, 
each  one  of  which  is  so  distinct  from  the  other  as  to  have 
been  regarded  as  a  separate  species.  Among  the  most 
marked  varieties  or  species,  we  may  mention  the  fan-tailed 
pigeon,  in  which  the  number  of  tail  feathers  has  been 
increased  from  ten  or  twelve,  to  thirty  or  forty,  the  pouter 
which  is  endowed  with  an  enormous  crop  distensible  with 
air,  pigeons  with  periwigs,  or  with  peculiar,  often  grotesque 
transformations  of  the  beak  and  feet,  pigeons  with  singular 
habits,  as  carriers,  or,  most  remarkable  of  all,  as  tumblers. 

The    alterations    thus    artificially  effected    may  extend 


94  THE  STRUGGLE  FOR  EXISTENCE. 

even  to  the  skeleton,  so  that  the  shape  or  number  of 
its  most  essential  bones  may  be  modified  in  a  high  degree. 
Thus  John  Sebright,  a  celebrated  London  pigeon  fancier, 
absolutely  maintained  that  he  could  produce  in  pigeons 
any  variety  of  external  form  in  one  year,  and  any  change 
in  the  bones  in  five  years.  And  yet  all  these  varieties,  thus 
artificially  or  naturally  produced,  are  now  known  to  be 
descended  from  the  primary  wild  blue  rock  pigeon.  Chickens 
have  been  produced  by  artificial  selection  with  beaks  so 
short  as  to  be  incapable  of  fracturing  and  escaping  from 
the  shell. 

The  same  deviations  of  form  have  been  noticed  in  all  the 
domesticated  animals.  The  numerous  varieties  or  species 
of  rabbits  are  all  derived  from  the  common  gray  rabbit, 
the  various  species  of  horse  from  the  zebra  or  quagga ;  in 
short,  all  domesticated  animals,  and  plants  may  be  now 
readily  traced  back  to  primitive  types,  to  which  they 
naturally  revert  again,  if  allowed  to  run  or  grow  wild. 
.  Having  observed  thus  the  radical  changes  of  form  which 
man  is  able  to  produce,  Mr.  Darwin  undertook  to  discover 
some  force  or  cause  in  nature  which  might  effect  the  same 
changes.  Here  it  was  that  the  thought  ''flashed"  upon  him, 
after  a  perusal  of  Malthus'  work,  of  the 

Struggle  for  Existence 

entailed  by  numbers,  and  the  survival  of  the  individual  or 
individuals  most  favored  in  some  peculiarity,  best  adapted 
to  the  surrounding  conditions. 

The  explanation  of  the  varieties  in  the  forms  of  life, 
by  means  of  natural  causes,  hinges  upon  the  really  appall- 
ing numbers  of  each  species  produced.  Linnaeus  calculated 
that  if  an  annual  plant  produced  only  two  seeds  (and  there 
is  not  one  which  produces  so  few)  it  would  yield  in  twenty 
years  a  million  of  individuals.     Darwin  has  shown   us  of 


THE  STRUGGLE  FOR  EXISTENCE.  95 

elephants,  which  are  the  slowest  of  all  animals  to  increase, 
that  in  750  years,  the  descendants  of  a  single  pair  would 
amount  to  nineteen  millions  of  individuals,  that  is,  suppos- 
ing that  every  elephant,  during  its  period  of  fertility  (from 
the  80th  to  the  90th  year),  produced  only  three  pairs  of 
young,  and  survived  itself  to  its  hundredth  year.  If  we  go 
down  much  lower  in  the  scale  of  animal  life,  go  down  to 
the  microscopic  infusoria,  we  find  there  numbers  which 
absolutely  daze  us  with  their  magnitude.  Thus,  Davaine 
has  calculated  that  a  single  bacterium  particle  would,  in 
the  course  of  twenty-four  hours,  become  the  parent  of  409G 
such  particles,  in  forty-eight  hours,  to  over  16,700  such 
particles,  and  between  the  sixtieth  and  sixty-second  hours, 
their  numbers  attain  to  one  to  seventy-one  trillions.  The 
swiftness  of  manifestation  and  virulence  of  expression  of 
the  contagious  diseases,  supposed  to  depend  upon  the 
presence  of  such  particles  in  the  blood,  corresponds  thus  to 
the  marvelous  fecundity  of  the  parent  germs.  If  each  spore 
of  one  species  only  of  the  higher  fungi  germinated  and 
reproduced  its  parent,  the  children  would,  in  the  first 
generation,  and  in  the  course  of  a  very  few  days,  form  a 
carpet  all  over  the  earth.  The  increase  in  the  number  of 
human  beings — without  any  hinderance — would  double 
the  total  every  twenty-five  years.  In  every  century  the  whole 
number  wTould  increase  sixteen  fold.  "The  population  of 
the  United  States  alone  would  require,  unchecked,  but  650 
years  to  cover  the  whole  terraqueous  globe  so  thickly,  that 
four  men  would  have  to  stand  on  each  square  yard  of 
surface." 

But  even  this  number  of  births  conveys  only  a  faint  idea 
of  the  numbers  of  ova,  which  never  develop  at  all.  Every 
joint  of  the  tape- worm,  for  instance,  contains  thousands  of 
eggs,  which,  fortunately  for  mankind,  fail  to  find  conditions 
for  development.    The  number  of  ova  in  the  human  being 


96  NATTJKAL  SELECTION". 

is  no  less  marvelous.  The  recent  investigations  of  Sappey, 
respecting  the  number  of  ova  developed  and  undeveloped 
in  the  human  female,  show  that  they  exist,  at  the  period  of 
full  adolescence,  to  the  number  of  nearly  seven  hundred 
thousand.  Even  the  more  temperate  estimate  of  Henle 
puts  the  original  number  of  ova  at  not  less  than  36,000  for 
each  ovary. 

Millions,  billions,  trillions  of  living  eggs  are  lost  in 
animal  life  ;  here  and  there  one  is  born  :  and  of  the  millions 
born,  here  and  there  one  survives.  Among  the  survivors, 
competition  begins  at  once  for  the  limited  means  of  sub- 
sistence. "Every  organism  struggles  from  the  commence- 
ment of  its  life  with  a  host  of  enemies.  It  struggles  against 
animals  which  feed  on  it,  for  which  it  is  the  natural  food  ; 
it  struggles  against  animals  of  prey  and  parasites,  it  struggles 
against  all  kinds  of  inorganic  influences,  against  heat  and 
cold,  against  the  weather,  and  above  all,  and  most  bitterly 
of  all,  against  organisms  most  like  itself."  Whichever 
individual  among  animals  and  plants  has  some  advantage, 
will  be  the  individual  to  live,  thrive,  and  propagate  its  kind. 
This  constitutes  what  is  known  as 

Natural  Selection. 

Here  comes,  for  instance,  a  summer  of  unusual  drought. 
Thousands  of  plants  perish  for  want  of  water ;  a  few  happen 
to  have  hairy  leaves.  The  hairs  on  the  leaves  are  hygrcn 
scopic.  They  furnish  a  larger  surface  for  the  absorption  of 
water,  so  the  hairy  plants  survive  the  drought,  and  propa- 
gate their  kind.  Next  summer,  most  of  the  plants  have 
hairy  leaves.  Island  insects  are  wingless,  or  have  wings  re- 
duced to  almost  rudimentary  state,  while  the  same  species 
on  continents  have  fully  developed  wings.  Wings  are  a 
great  disadvantage  to  island  insects,  because,  in  soaring 
aloft,  they  are  swept  out  to  sea  and  drown.    The  insects 


NATURAL   SELECTION.  97 

having  the  wings  least  developed  are,  on  islands,  the  favored 
of  nature  to  survive  and  propagate  their  kind.  Natural 
causes  thus  easily  explain  the  perfect  adaptation  of  struc- 
ture to  conditions  without  resort  to  supernatural  design* 

Protective   Colors. 

Another  example  of  natural  selection  is  the  coloring  of 
the  various  animals.  Some  of  these  colors  are  distinctly 
protective.  These  animals  resemble  in  hue  surrounding 
inanimate  objects.  Arctic  animals,  bears,  etc.,  are  white 
like  the  ice  and  snow.  In  summer,  when  the  snow  vanishes, 
they  too  change  color  to  resemble  the  gray  or  black  earth. 
Desert  animals,  foxes,  gazelles,  lions,  are  sandy  or  fawn- 
colored.  The  birds  and  insects  of  the  tropical  forests  are 
green ;  butterflies  are  variegated  like  the  flowers ;  fishes, 
molluscs,  etc.,  are  colorless,  or  are  scarcely  distinguished  in 
the  sea.  Through  the  crystalline  bodies  of  many  fishes  and 
pelagic  animals,  the  words  on  a  printed  page  may  be  dis- 
tinctly read.  Eeptiles  are  spotted  and  striped  and  scaled 
like  the  bark  of  trees,  or  reeds,  or  leafy  soil  upon  which  they 
crawl.  These  colors  conceal  the  animals  from  their  foes,  or 
enable  them  to  creep  unobserved  upon  their  prey,  and  the 
individual  whose  color  most  nearly  resembles  his  surround- 
ings is  the  favored  of  nature  to  survive  and  propagate  his 
kind. 

Warning   Colors. 

r 

Other  colors,  Mr.  Wallace  has  shown  us,  are  warning 
signals.  Certain  butterflies  and  frogs  are  large  and  vividly 
colored.  They  fly  slowly.  It  is  to  their  advantage  to  be 
seen,  because  they  are  unfit  for  food,  their  juices  having  a 
disgusting  odor  and  taste  to  birds  and  beasts  of  prey.  Bees 
and  wasps,  stinging  animals,  are  often  thus  distinctly  colored 
to  their  safety.    Mr.  Belt  tells  us  that  in  Nicaragua,  there  is  a 


98  SEXUAL  SELECTION". 

frog  which  is  very  abundant,  which  hops  about  in  the  day 
time,  which  never  hides  himself,  and  which  is  gorgeously 
colored  with  red  and  blue.  Frogs  are  usually  green,  brown, 
or  earth-colored,  feed  mostly  at  night,  and  are  all  eaten  by 
snakes  and  birds.  Mr.  Belt  was  convinced,  therefore,  that 
this  colored  frog  was  uneatable.  He  took  one  home  and 
threw  it  to  his  ducks  and  fowls;  "but  all  refused  to  touch 
it,  except  one  young  duck,  which  took  the  frog  into  its 
mouth,  but  dropped  it  directly,  and  went  about  jerking  its 
head  as  if  trying  to  get  rid  of  something  nasty." 

Sexual  Selection. 

Natural  selection  again  comes  into  play  in  the  difference 
that  exists  between  the  two  sexes  of  all  animals.  In  nearly 
all  cases,  the  male  animal  is  the  larger  and  more  beautiful. 
It  has  weapons  of  offense,  tusks,  spurs,  antlers,  teeth,  etc. ; 
and  of  defense,  manes  to  protect  the  vessels  of  the  neck, 
skin  coverings,  etc.,  in  its  combats  with  rivals  to  secure 
possession  of  the  female.  Locked  skeletons  of  stags  are 
sometimes  found  in  the  depth  of  forests,  so  many  monu- 
ments of  such  battle-fields.  The  choice  of  the  female  falls 
upon  "the  most  vigorous,  defiant,  and  mettlesome  male," 
and  these  peculiarities  are  transmitted  to  the  offspring,  or 
she  selects  the  male  endowed  with  the  richest  ornaments  in 
plumage,  or  hue,  or  is  attracted  to  the  most  melodious 
voice,  or  sound,  as  in  the  case  of  singing  birds,  crickets, 
locusts,  etc.  Prof.  Weismann  has  recently  shown  that  fresh 
water  fleas  are  brilliantly  colored  with  patches  of  scarlet 
and  blue  as  charms  for  the  opposite  sex,  and  that  the  masks 
with  staring  eyes  upon  the  feeble  caterpillar's  back  are 
"startling"  or  "terrifying"  colors  (schreclcfarben)  "that  he 
may  enjoy  the  privileges  so  usually  gained  by  the  ass  in  the 
lion's  skin."  The  choice  in  pairing  resulting  from  the  ex- 
hibition of  these  attractions,  offered  by  the  courting  sex, 


SEXUAL   SELECTION.  99 

constitutes  what  is  technically  styled  sexual  selection.  "We 
have  no  time  to  fully  consider  the  multiform  manifesta- 
tions of  sexual  selection.  You  may  recall,  perhaps,  the 
curious  example  mentioned  by  Tom  Moore,  in  his  "Loves 
of  the  Angels" : 

"For  well  I  know  the  luster  shed 
From  cherub  wings  when  proudliest  spread, 
"Was  in  its  nature  lambent,  pure 
And  innocent,  as  is  the  light 
The  glow-worm  hangs  out  to  allure 
Her  mate  to  her  queen  bower  at  night." 

The  rattle  of  the  rattlesnake  is  also  such  a  call,  and  not  a 
means  of  "striking  terror,"  and  thus  causing  its  natural 
food  to  escape.  "What  an  idiotic  idea,  this  last,  that  an 
animal  should  chase  away  its  own  food ! 

It  need  scarcely  be  said  that  all  these  actions  of  natural 
and  sexual  selections  are  just  as  marked  in  man  as  in  the 
lower  animals.  The  male  captured  the  female,  vi  et  armis, 
in  the  middle  ages,  just  as  now  in  savage  life.  The  strongest 
won.  Nearly  all  the  more  modern  duels  concern  the  posses- 
sion of  an  individual  among  the  fair  sex.  Charm  of  face 
and  form,  of  voice  and  dress,  are  just  as  potent  in  man  as 
in  the  lower  animals.  The  top-knots  and  hirsute  append- 
ages of  the  monkey  find  their  analogues  in  the  tonsorial 
decorations  of  man.  The  female  bower-bird  is  no  less 
attracted  by  the  decorations  in  the  way  of  shells  and 
feathers  and  colored  stones,  with  which  the  male  bestrews 
his  nest,  than  is  the  female  of  man  by  a  solid  bank  account, 
and  a  three-story  front.  But  there  are,  in  continual  opera- 
tion among  the  sexes,  other  higher  influences  than  mere 
personal  attractions,  superiorities  of  mind  and  character, 
the  conjunctions  of  which  secure  to  the  human  race  a  ten- 
dency towards  gradual  perfection. 


100  COMPLICATIONS   IN   NATURAL   SELECTION. 

Complications    in   Natural  Selection. 

The  laws  of  natural  selection  do  not  always  work,  how- 
ever, in  such  plain  and  simple  channels.  The  most  compli- 
cated conditions  and  relations  sometimes  manifest,  render- 
ing the  tracing  of  the  action  of  natural  selection  exceedingly 
difficult. 

Thus,  there  are  small  coral  islands,  whose  inhabitants  live 
almost  entirely  upon  the  fruit  of  a  species  of  palm.  The 
fructification  of  this  palm  is  exclusively  effected  by  insects, 
which,  in  feeding  upon  the  flower,  bring  the  pollen 
grains  into  contact  with  the  ova.  The  existence  of  these 
useful  insects  is  endangered  by  insect-eating  birds,  which 
are,  in  turn,  pursued  by  birds  of  prey.  The  birds  of  prey, 
however,  often  succumb  to  the  attack  of  a  small  parasitical 
mite,  which  develops  in  millons  in  their  feathers.  This 
small  dangerous  parasite  again  may  be  killed  by  parasitical 
moulds.  So  moulds,  birds  of  prey  and  insects,  favor  the 
prosperity  of  the  palm,  and  consequently  of  man;  while 
the  parasite,  insect-eating  birds,  etc.,  put  them  both  in 
danger  of  extermination.  I  cite  another  case  almost  literally 
as  given  by  Haeckel.  Paraguay  is  noted  for  the  fact  that 
it  contains  no  wild  cattle  of  any  kind.  All  the  countries 
around  Paraguay  abound  in  wild  cattle,  but  there  are  none 
in  this  country  but  the  domesticated  cattle.  This  is  due  to 
the  fact  that  there  is  an  insect  in  Paraguay  which  lays  its 
eggs  in  the  umbilical  cord  of  the  young  animals,  and  finally 
destroys  the  animal  altogether,  If  some  animal  should  arise 
which  should  prey  upon  this  insect,  wild  cattle  would  be 
again  seen  on  the  plains  of  Paraguay.  As  these  animals 
would  consume  some  of  the  fauna  and  flora  of  the  country, 
it  is  easy  to  see  how  its  botany  might  be  entirely  changed, 
and  in  the  course  of  this  change,  the  human  population 
would  have  to  alter. 


COMPLICATIONS  IX   NATURAL  SELECTION.  101 

Mr.  Darwin's  graphic  description  of  the  relation  between 
cats  and  red  clover  is  always  quoted  in  this  connection. 

The  red  clover  of  England,  which  forms  the  very  Lest 
fodder  for  cattle,  requires  the  visit  of  humming  "bees  to  ob- 
tain the  formation  of  seeds.  These  insects,  while  sucking 
the  honey  from  the  bottom  of  the  flower,  bring  the  pollen 
in  contact  with  the  stigma,  and  thus  cause  the  fructification 
of  the  flower,  which  never  takes  place  without  it.  Red 
clover  which  is  not  visited  by  humming  bees,  does  not  yield 
a  single  seed.  Now  the  number  of  bees  is  determined  by 
the  number  of  their  enemies,  the  most  destructive  of  which 
are  the  field  mice.  The  more  the  field  mice  predominate, 
the  less  the  clover  is  fructified.  The  number  of  field  mice 
again  depends  upon  the  number  of  their,  enemies,  which 
here,  as  everywhere,  are  chiefly  cats.  Hence,  in  the  number 
of  villages  and  towns  wThere  many  cats  are  kept  there  are 
plenty  of  bees  and  plenty  of  red  clover. 

Now,  as  the  cattle  which  feed  on  the  red  clover  furnish 
the  best  roast  beef  in  the  world,  and  as  it  has  been  conclu- 
sively established  that  superiority  of  food  determines,  in 
great  degree,  superiority  of  body  and  mind,  and  hence 
superiority  among  nations,  it  is  an  easy  inference  to  ascribe 
this  superiority,  with  Carl  Yogt,  to  the  influence  of  the  cats 
which  kill  the  mice,  which  kill  the  bees,  etc. ;  much  in  the 
order  of  the  house  that  Jack  built.  Mr.  Huxley,  indeed,  is 
unwilling  to  stop  here,  as  he  traces  back  the  chain  of  causes 
to  those  who  cherish  cats,  the  elderly  unmarried  ladies,  to 
whom  due  homage  should  be  paid  for  having  secured  the 
wealth  and  prosperity  of  the  great  English  nation. 

A  striking  example  of  a  radical  change  effected  in  plant 
life  by  a  complicated  natural  selection  is  related  by  Francis 
Darwin,  in  his  account  of  the  analogies  between  animals 
and  plants.  The  bright  colors  and  sweet  smells  of  flowers 
are,  as  is  now  well  known,  only  allurements  held  out  to  in- 


102         PRESERVATION  OF  INDIVIDUAL  AND  OE  RACE. 

sects  to  entice  them  to  carry  the  fertilising  pollen  from  one 
flower  to  another.  But  there  is  a  wild  cabhage-like  plant  in 
Kerguelen's  land,  which  alone  of  the  enormous  order  of  the 
Cruciferse,  is  fertilised  by  the  wind.  The  change  in  the  life 
history  of  this  plant,  which  makes  it  such  an  exception,  de- 
pends upon  the  fact  that  the  insects  in  Kerguelen's  land  are 
wingless,  and  are  therefore  bad  distributors  of  pollen.  The 
insects  are  wingless,  because  the  winged  insects  have  been 
blown  out  to  sea  and  drowned.  "Thus  the  pollen  of  the 
cabbage  has  to  learn  to  fly,  because  the  insects  will  not  fly 
for  it." 

I  quote  one  further  simpler  instance  of  the  action  of 
natural  selection,  because  it  contains  in  itself  alone  the  ex- 
planation of  the  action  of  natural  selection  in  its  widest  sense. 

Some  sailors  once  let  loose  upon  an  isolated  uninhabited 
island  in  the  Pacific  Ocean  a  couple  (male  and  female)  of  pigs. 
They  had,  an  excess  of  these  animals  on  board,  and  they 
turned  them  out  to  breed,  perchance,  for  future  ship- 
wrecked mariners.  The  pigs  found  upon  the  island  an 
abundance  of  food,  and  no  enemies.  They  bred  with  char- 
acteristic fecundity,  until  the  island  fairly  swarmed  with 
pigs.  Subsequently,  other  sailors  put  upon  the  island  a 
couple  of  dogs.  The  pigs  became  the  food  for  the  dogs. 
The  dogs  multiplied,  and  the  pigs  decreased.  Finally  all 
the  pigs  were  destroyed,  and  then,  of  course,  starvation 
killed  the  dogs.  But  during  the  long  periods  of  super- 
abundance, abundance,  and  want  of  food,  various  modifica-. 
tions  ensued  in  the  forms  of  both  animals,  making  at 
different  times,  species  very  different  from  those  first  intro- 
duced. 

Preservation   of  the  Individual  and  of   the  Race. 

Here  operated  upon  this  isolated  island  in  the  Pacific 
Ocean  the  two  great  causes,  everywhere   at  work,  one  of 


GENERAL  SUMMARY.  103 

which  insures  the  perpetuity  of  form,  at  least  for  a  long 
time,  while'  the  other  insures  its  mutation.  Of  these  two 
great  causes,  one  is  the  instinct  which  secures  the  preserva- 
tion of  the  species,  viz.,  that  of  reproduction  and  the  other 
is  the  instinct  which  secures  the  preservation  of  the  indi- 
vidual, viz.,  hunger. 
So  said  Schiller  long  ago  : 

Einstweilen  bis  den  Bau  der  Welt; 
Philosophic  zusammenha.lt, 
Erhalt  sich  ihr  Getriebe, 
Durch  Hunger  und  durch  Liebe. 

Which  I  have  ventured  to  translate  very  liberally : 

"Until  the  earth  is  all  explained, 
Without  call  on  power  above, 
Its  working's  still  will  be  sustained 
By  Hunger  and  by  Love." 

I  present  you,  thus,  in  this  series  of  lectures,  the  barest  out- 
lines of  the  state  of  existing  knowledge  concerning  the 
origin  and  evolution  of  life,  as  explained  by  natural  causes. 
We  have  considered  the  subject  from  the  standpoints  of 
palaeontology,  comparative  anatomy,  and  natural  selection 
only.  Of  these  fields,  wTe  have  had  time  to  take  only 
bird's-eye  views.  The  proofs  offered  by  philology,  the  study 
of  languages,  and  chorography,  the  geographical  distribution 
of  animals,  are  no  less  clear  and  convincing.  But  these 
studies  are  entirely  out  of  our  special  province.  I  refer  you 
to  the  now  familiar  works  of  Mr.  Darwin,  of  Mr.  Wallace — 
whose  discoveries  really  forced  upon  Mr.  Darwin  the  publi- 
cation of  his  own  views,  prematurely,  as  he  then  believed — 
of  Haeckel,  Schleicher,  Geiger,  Steinthal,  and  the  recent 
epitome  by  Oscar  Schmidt,  for  a  full  and  complete  state- 
ment of  all  the  evidence.  Evidence  which  may  now  be 
likened  to  an  arch,  composed  of  many  pieces,  with  palaeon- 


104  '  GENERAL  SUMMARY. 

tology  and  comparative  anatomy  as  foundation  stones  at 
either  end,  and  natural  selection  as  the  key-stone  in  its 
center. 

I  do  not  know  how  I  may  better  close  this  part  of  our 
subject,  now,  than  by  repeating,  with  very  slight  modifica- 
tion, the  recapitulation  of  Mr.  Darwin  at  the  close  of  his 
first  and  greatest  work,  the  "Origin  of  Species."  It  is  to 
his  genius  that  we  owe  the  whole  elaboration  and  proof  of 
the  "Theory  of  Descent,"  as  first  advanced  by  Lamarck  in 
1809,  as  it  is  to  his  marvelous  collection  of  facts,  his  clear- 
ness of  statement,  and  his  candor,  that  is  due  its  general 
adoption  in  every  field  of  science  to-day  : 

It  is  interesting  to  contemplate  a  tangled  bank,  clothed 
with  many  plants  of  many  kinds,  with  birds  singing  in  the 
bushes,  insects  flitting  among  the  flowers,  and  worms  crawl- 
ing upon  the  bosom  of  the  great  mother  earth.  It  is  inter- 
esting to  contemplate  all  these  things,  and  to  reflect  that 
these  elaborately  constructed  forms,  so  different  from  each 
other,  yet  so  dependent  upon  each  other,  have  all  been  pro- 
duced by  laws  continually  acting  around  us.  The  laws  of 
growth  and  reproduction  ;  a  ratio  of  increase  so  high  as  to 
lead  to  a  struggle  for  life,  as  a  consequence  to  natural  selec- 
tion, and  the  slow  but  certain  improvement  of  forms.  Thus, 
from  the  war  of  nature,  from  famine,  and  from  death,  the 
most  exalted  object  which  we  are  capable  of  conceiving, 
namely,  the  production  of  the  higher  animals,  directly  and 
inevitably  follows.  There  is  a  grandeur  in  this  view  of  life, 
with  its  several  powers,  having  been  originally  breathed 
by  the  Creator  into  a  few  forms,  or  into  one  ;  and  in  that, 
whilst  this  planet  has  gone  cycling  on,  according  to  a  fixed 
lav/  of  gravity — from  so  simple  a  beginning — endless  forms, 
most  beautiful,  most  varied,  and  most  wonderful,  have 
been,  and  are  being  evolved. 


Fig.  9.— The 

Amoeba. 

(p.  114) 


Fig.  10. — The  Ovnm, 
a  typical  cell,    a,  cell    Fig. ii.-Seg-    Fig.  I2.-Furth-  sSgeSk)n     "  c?S 

wall.    4,  cell  contents    mentation   of   er  process  of  seg-  segmentation.   «,  ecu 
or  protoplasm,    c,  nu-  the  cell,  a,  cell  mentation,  a,  cell  wall.      b,   subdivided 
cleus   and    nucleolus,  wall,    b,  subdi-  wall,  b,  subdivid-  ceils, 
(pp.  109-113)  vided  cell       ed  cells,  the  low- 

showing  divi-       est  of  which 

sion    of   nucle-    shows  a  subdi- 

olus.     (p.  144)       vided  nucleus. 


Fig.  14. — Section  of  skin  of  chameleon 
showing  pigment  cellsm  retracted  (active) 
state,     (p.  117) 


Fig1.    15.— The  same   showing  pigment 
cells  in  protruded  (relaxed)  state,     (p.  117) 


Fig.  16. — Penetration  of  ovum  (without 
wall)  by  the  spermatozoid.  a,  spermatozoid. 
b,  enveloping  mucus.  £,  yolk  or  protoplasm, 
(p.  124) 


Fig.  17. — The  same.  Further  process  of 
penetration,  a,  spermatozoid.  £}  space  in 
mucus  left  by  retreating  yolk.  cy  mucus. 
d,  yolk.     (p.  124) 


Fig.  18. — The  impregnated 
ovum,  a,  zonapellucida  (wall). 
b,  sperm  nucleus,  c,  nucleus 
of  the  ovum.     (p.  125) 


Fig.  19.— The  impregnated  Fig.  20.— The  ovum  at  full 
ovum,  a,  the  nucleus  result-  maturity,  c,  the  micropcle.  by 
ing  from  the  fusion  of  the  the  zona  pellucida  (wall)  show- 
sperm  and  germ  nucleus.  6,  ing  the  pore  canals  (striae).  £, 
the  cell  wall.     (p.  125)  the  seminal  cord.  </,  the  germ- 

inal   vesicle    (nucleus    of   the 
ovum),     (p.  125) 


THE    CELL    AND    ITS     REPRODUCTION. 


PROTOPLASM   AND  ITS  PROPERTIES.  105 


LECTURE    VI. 
PROTOPLASM  AND  ITS  PROPERTIES. 

CONTENTS. 

The  History  of  Histology — The  Invention  and  Use  of  the  Microscope 
.  — The  Discovery  and  Doctrine  of  The  Cell — Derivation  and  Im- 
port of  The  Cell— The  Cell  Wall— The  Nucleus  and  Nucleolus— The 
Cell  Contents  or  Protoplasm — The  Amceba — The  Properties  of  Proto- 
plasm— Motion — The  Color  Changes  of  the  Chameleon — Ciliary  Mo- 
tion— Motion  of  Other  Cells — Molecular  Motion — Molecular  Changes 
in  the  Ovum — Parthenogenesis — Motion  as  the  Essence  of  Repro- 
duction 

We  have  already  seen  that  different  machinery  or  appa- 
ratus is  required  to  effect  the  various  changes  of  matter  aud 
force.  We  convert  chemical  force  or  affinity  into  galvanism 
in  galvanic  cups,  magnetism  into  electricity  with  iron  bars 
and  wires,  heat  into  motion  with  boilers,  cylinders  and 
pistons,  etc.  That  physical  may  be  converted  into  physi- 
ological force  there  is  requisite  animal  or  vegetable  matter. 
In  our  day,  we  name  this  matter  or  apparatus  protoplasm. 
In  complicated  arrangement  we  say  the  protoplasm  consti- 
tutes an  organism.  In  the  study  of  physiology  we  are 
engaged  with  the  construction  of  the  organism  (instrument) 
which  sets  the  force  free,  with  the  mode  of  action  by  which 
it  is  changed  to  other  forms,  and  with  the  various  forms 
under  which  it  reappears. 

As  there  can  be  no  force  without  matter,  there  can  be  no 
knowledge  of  action  without  knowledge  of  construction. 

Our  knowledge  of  the 

Construction  of  the  Body 
from  an  historical  standpoint  naturally   falls   under   two 


106  INTENTION  AND  USE  OF  THE  MICROSCOPE. 

divisions,  that  acquired  before  the  discovery  of  the  micro- 
scope and  that  acquired  since. 

The  older  anatomists  and  physiologists  made  us  acquainted 
with  everything  that  could  be  seen  with  the  naked  eye. 
They  described  the  position  and  relations  of  all  the  organs 
of  the  body,  defined  what  we  now  consider  the  grosser 
characteristics  of  the  various  tissues  and  established  their 
general  properties.  The  older  anatomists  and  physiologists 
drew  what  we  might  call  the  general  outlines  of  all  the 
structures  of  the  body,  and  with  a  fidelity  which  is  the 
highest  tribute  to  their  diligence  and  skill.  We  read  with 
astonishment  the  accurate  descriptions  of  Vesalius  and 
Fallopius,  of  Soemmering  and  Bichat,  and  with  admiration 
the  ingenious  experiments  of  Harvey  and  De  Graaf.  But 
the  older  anatomists  and  physiologists  could  not  penetrate 
to  the  minute  construction  of  the  tissues.  Histology  in  tlje 
true  sense  of  the  term,  was  a  sealed  and  unopened  volume. 
It  was  only  with  the  invention  of  the  microscope,  more 
especially  with  its  perfection,  that  such  studies  became 
possible. 

The  Invention  and   Use  of  the  Microscope. 

The  honor  of  this  invention  is  claimed  by  the  French, 
the  Italians  and  the  Dutch.  The  truth  is,  however,  that 
lenses  were  in  use,  as  such,  in  ancient  times.  Aristophanes 
informs  us  that  globules  of  glass,  known  as  "burning  spheres," 
were  sold  by  the  grocers  of  Athens.  It  is  hardly  possible  to 
imagine  that  the  magnifying  power  of  these  spheres  could 
have  escaped  observation  ;  indeed,  we  read  in  Seneca  among 
the  "Natural  Questions"  the  following  statement  in  proof. 
"However  small  and  obscure  the  writing  may  be,  it  appears 
larger  and  clearer  when  viewed  through  a  globule  of  glass 
filled  with  water."  So-callecl  "water  microscopes,"  consisting 
simply  of  a  drop  of  water  attached  to  the  end  of  a  bras3 


INVENTION  AND  USE  OF  THE  MICROSCOPE.  107 

wire,  were  still  in  common  use  at  the  beginning  of  the  17th 
century.  We  have  evidence  of  the  ancient  use  of  lenses 
for  magnification  in  the  engraving  of  characters  and  letters 
too  small  to  be  visible  to  the  naked  eye.  We  would 
be  hardly  prepared  to  admit  that  vision  was  keener  centuries 
ago  than  now,  so  that  we  must  believe  the  eye  to  have  been 
aided  with  the  lens.  Thus  Cicero  speaks  of  an  Iliad  of 
Homer  small  enough  to  have  been  enclosed  in  a  nutshell, 
and  Pliny  mentions  that  Myrmecides  "executed  in  ivory  a 
square  figure  which  a  fly  covered  with  its  wings."  In  fact, 
veritable  lenses  have  been  exhumed  from  Nineveh  and 
Herculaneum. 

The  microscope,  thus,  like  every  other  invention,  was  in 
no  sense  a  sudden  discovery.  It  reached  from  time  to  time 
a  process  of  development,  to  then  fall  into  oblivion  for 
years,  or  for  centuries,  and  be  again  revived  with  improve- 
ments to  give  it  new  impulse  in  its  gradual  evolution. 

The  first  individual  to  give  the  microscope  permanent 
place  among  the  acquisitions  to  the  study  of  nature  was 
Zacharias  Janssens,  a  celebrated  optician  in  Holland 
(1590).  As  every  discovery  in  every  field  of  science  sooner  or 
later  comes  to  be  utilised  in  the  study  of  medicine,  it  is  not 
surprising  to  learn  that  scarcely  25  years  had  elapsed  before 
Italian  and  Dutch  anatomists  (Malpighi  and  Leeuwenhoek, 
1G28-1723),  were  busy  with  the  microscope  in  the  study  of 
the  human  body.  Though  the  instruments  then  in  use 
were  exceedingly  clumsy  and  defective,  it  was  with  their 
aid  that  the  most  remarkable  phenomena  in  nature  were  dis- 
closed. The  last  link  in  the  chain  of  evidence  establishing 
the  circulation  of  the  blood  was  only  completed  with  the 
discovery  of  the  blood  corpuscles  and  capillary  net  work  by 
Malpighi ;  whose  name  is  still  transmitted  with  histological 
elements  in  the  kidneys  and  spleen ;  and  the  essential 
element  of  the  semen — to  select  only  the  most  striking  ex- 


108  DISCOVERY  AND  DOCTRINE  OF  THE  CELL. 

amples — the  spermatozoids  were  first  described  by  Leeuwen- 
hoek,  to  whom  they  had  been  shown  by  one  of  his  students, 
Von  Hamm,  in  1677. 

But  the  revelations  of  the  microscope,  at  this  period  in  its 
history,  were,  as  Frey  remarks,  "more  in  keeping  with  the 
curiosity  loving  spirit  of  the  times,  than  with  any  definite 
principle  or  basis  of.  investigation."  Penetration  to  funda- 
mental structure  was  still  impossible,  until  the  study  of 
histology  had  received  fresh  impetus  in  steps  towards  the 
perfection  of  the  microscope,  taken  first  by  Dutch  and 
German  opticians,  Van  Deyl  and  Fraunhofer,  in  the  first 
decade  of  the  present  century.  The  simple  lense3  of 
Malpighi  and  Leeuwenhoek  were  now  speedily  duplicated 
many  times,  combinations  of  different  lenses,  of  different 
kinds  of  glasS)  were  soon  arranged  to  obviate  aberrations  of 
sphericity  and  chromatism,  and  "the  clumsy  and  deceptive 
implement  of  the  last  century  was  transformed  into  the 
elegant  and  accurate  instrument  of  the  present  day." 

The  Discovery  and  Doctrine  of  The   Cell. 

Now,  then,  for  the  first  time,  was  rendered  possible  a  pene- 
tration to  the  minute  construction  of  the  various  tissues. 
A  host  of  observers  were  soon  engaged  in  histological  study, 
Miiller,  Purkinje,  Wagner,  Valentin,  Henle,  among  the 
pioneers,  and  one  distinguished  above  all  the  rest,  "not  only 
on  account  of  his  own  researches,  but  also  on  account  of  his 
collocation  and  arrangement  of  the  discoveries  of  others, 
and  his  deductions  thence  of  general  laws,  which  are  to  be 
regarded  as  the  foundations  of  modern  histology"  (Tizzoni). 
The  "cell  doctrine,"  as  established  by  C.  Th.  Schwann 
(1838),  marks  the  first  great  epoch  in  the  modern  science  of 
histology. 

According  to  this  doctrine,  as  subsequently  elaborated 
more  especially  by  lleichert,  Kolliker  and  Virchow,  every 


SHAPE   AND   SIZE   OE   CELLS-  109 

tissue  and  organ  of  every, living  thing,  plant  or  animal,  is 
built  up  of  an  aggregate  of  cells,  or  the  products  of  cells. 
An  organ,  the  whole  organism,  is  an  union  of  cells,  just  as  a 
state  or  association  is  an  assemblage  of  individuals.  "The 
greatest  discovery  of  the  microscope  is  not,  as  might  at  first 
appear,  the  revelation  of  a  new  world  of  microscopic  life ; 
it  is  the  discovery  of  the  simple,  elementary  structure  of  the 
human  body,  and  of  every  organised  body  in  nature  ;  it  is 
the  astonishing  discovery  that  every  living  thing,  from  man 
to  the  invisible  insect,  from  the  oak  to  the  infusoria,  how- 
ever different  their  apparent  natures,  are  constructed  upon 
one  plan,  from  one  and  the  same  elementary  form"  (Banke). 

Shape  and  Size    of  Cells. 

^  A  typical  cell  is  a  spheroidal  body,  consisting  of  an 
envelop  (or  cell  wall),  of  so-called  cell  contents  (protoplasm, 
bioplasm,  cytoplasm,  sarcode,  etc.),  including  a  smaller 
eccentrically  situated  spheroidal  mass,  the  nucleus,  which 
in  turn  includes  one  or  more  still  smaller  particles,  nucleoli.  v 

Such  a  cell  is  the  ovum,  or  primordial  cell,  from  which 
every  organised  body  develops.  The  various  parts  of  the 
ovum  have,  however,  been  dignified  with  special  names. 
Thus  the  translucent  wall  is  the  zona  pellucida,  the  contents 
form  the  yolk,  the  nucleus  is  called  the  germinal  vesicle,  and 
the  nucleolus  is  the  germinal  spot.  The  ovum  differs  from 
all  other  cells  in  the  body  of  man  in  being  visible  to  the 
naked  eye.     It  is  the  largest  cell  in  the  body,  measuring 

*  tto  °£  an  inck  (0.21  mm.)  in  diameter.  Hence,  in  describ- 
ing the  size  of  cells,  the  ovum  is  put  at  one  extreme,  while 
at  the  other  is  placed  the   red  blood    corpuscle,  with  a 

^  diameter  of  -gJ^  of  an  inch  (0.0077  mm).  Cells  vary  in 
size  between  these  extremes.  There  is  full  as  great  variety 
in  shape.  Fat  cells  are  rounded,  liver  cells  polygonal, 
epithelial  cells  fiat  or  cylindrical,  muscle  cells  fusiform,  con- 


110  IMPORT   OF   THE  CELL. 

nective  tissue  cells  filiform,  while  bone  cells,  with  their 
radiating  canaliculi,  and  nerve  cells,  with  their  numerous 
poles  and  bright  nuclei,  present  very  peculiar,  stellate  or 
even  fantastic  shapes. 

The  whole  body  is  thus  reduced  to  cells  of  definite  size 
and  shape.  *  We  obtain,  thus,  the  ultimate  elements  of  organ- 
isation, v  '"'The  cell  theory  in  physiology  corresponds  to  the 
atom  theory  in  physics,  but  cells  have  the  advantage  over 
atoms,  of  being  visible  and  available"  (Kiiss). 

The  question  now  arises  which  of  the  constituents  of  the 
cell,  the  wall,  the  contents,  the  nucleus,  or  the  nucleolus,  is 
the  most  essential  element  ? 

Derivation  and  Import  of  the   Term. 

It  should  be  remarked  first  that  the  term  "cell"  has  now 
a  very  different  significance  from  its  first  use.  The  dis-' 
covery  of  Schwann  in  histology  was  really  based  upon  the 
discovery  of  Schleiden  in  botany,  that  sections  of  young 
plants  under  the  microscope  presented  the  appearance  of 
the  cells  of  the  honeycomb.  Schwann  observed  that 
epithelial  cells  present  the  same  appearance,  hence,  the  title 
of  his  work,  the  Uebereinstimmung ,  etc.,  the  similarity  or 
Identity  in  construction  of  animals  and  plants,  and  hence, 
the  term  cells.  The  first  intimation  of  the  cellular  struc- 
ture of  animal  tissue  was  that  of  Johannes  Miiller,  who 
showed  that  the  chorda  dorsalis  of  the  fish  consists  of  closely 
apposed  cells  with  peculiar  walls.  Miiller  also  first  distin- 
guished nuclei  in  the  analogous  cells  of  the  chorda  dorsalis 
of  the  frog.  Besides  the  interest  which  attaches  to  this 
structure  as  the  primitive  vertebral  column,  the  chorda 
dorsalis  has  also  the  additional  historical  interest  of  having 
been  the  tissue  in  which  "the  cell"  was  discovered. 

If  the  tail  of  a  dead  tad-pole,  after  having  been  for  24 
hours  in  water,  be  cut  through  at  its  point  of  origin  and  the 


THE  CELL  WALL.  HI 

chorda  dorsalis  expressed  by  gentle  pressure  from  the  head 
downwards,  suitable  particles  of  it  may  be  examined  under 
the  microscope  (best  with  a  6  per  cent,  solution  of  common 
salt).  The  cells  appear  of  irregular  polygonal  form,  those 
from  the  middle  of  the  chord  larger,  those  from  the 
periphery  smaller  (Gescheidlen).  We  have  now  the  picture 
first  seen  by  Schwann.  The  likeness  to  the  cells  of  the 
honeycomb  or  to  vegetable  cells  is  exact.  Tt  was  a  subse- 
quent elaboration  of  this  disclosure  at  the  hands  of  a  num- 
ber of  observers,  the  discovery  that  all  the  organs  and 
tissues  are  constructed  upon  the  same  plan,  so  that  the  cell 
in  modern  histology  means  more  than  mere  form  or  shape ; 
it  means  the  ground  plan,  the  origin  and  individuality,  the 
ultimate  anatomical  element,  the  chemical  laboratory,  and 
the  physical  and"  physiological  centre  in  which  all  the 
phenomena  of  life  are  evolved.  *" 

The    Cell    Wall 

As  to  the  relative  importance  of  the  various  constituents 
of  the  cell,  it  is  known  (Bergmann,  Bischoff,  Kolliker)  that 
the  embryonal  stage  of  certain  animals  exhibits  cells  com- 
posed of  nucleated  contents  entirely  deprived  of  a  wrall. 
Moreover  there  are  animals,  whose  whole  life  is  comprised 
within  the  narrow  circle  of  a  single  cell,  consisting  simply 
of  a  homogeneous  mass  of  contractile  substance,  without 
either  nucleus  or  wall.  Again,  there  are  forms  of  life,  con- 
sisting of  multiple  cells  or  aggregations  of  matter,  sponges, 
radiolarice,  etc.,  devoid  of  wall  and  nucleus.  So  Max 
Schultze  and  Lionel  Beale  regard  the  wall  as  an  addition, 
rather  than  as  a  necessary  constituent  of  the  cell.  Accord- 
ing to  Schultze,  the  subsequent  formation  of  the  cell  wall 
indicates  a  limitation  in  the  life  of  the  cell,  i.  e.,  it  is  a  sign 
of  decrepitude,  while  Beale  regards  the  wall  as  a  product 
of  the  cell,  the  formed  material,  in  distinction  to  the  form- 


112  THE  NUCLEUS  AND  NUCLEOLUS. 

ing,  or  germinal  matter,  the  protoplasm.  Kolliker  looks 
upon  the  cell  wall  as  the  sign  rather  of  full  development 
and  maturity.  The  cell  wall,  more  dense  and  firm  than  the 
.remaining  constituents,  is  the  protecting  envelop  of  the 
more  delicate  structure  within,  and  at  the  same  time  regu- 
lates diffusion  between  its  contents  and  circumambient 
media. 

Diffusion  is  effected  through  the  cell  wall,  when  homo- 
geneous in  structure,  by  simple  absorption  or  osmosis,  but  is 
more  directly  effected  in  some  cases  through  minute  canals, 
which  may  be  seen  in  transparent  cells  as  fine  rines  or 
striae  traversing  its  entire  thickness.  Thus  Virchow  men- 
tions having  seen  fat  globules  penetrating  from  the  intes- 
tinal canal  through  the  wall  of  the  cells  which  cover  the 
lacteals,  and  Lowe  describes  in  detail  the  penetration  by  the 
spermatozoid  of  the  zona  pellucida  (wall)  of  the  ovum 
through  one  large  opening,  the  micropyle,  or  through  one 
of  the  numerous  finer  canals  in  the  rest  of  the  wall. 

The  Nucleus    and  Nucleolus. 

The  nucleus  is  the  smaller,  separated  body,  of  various 
size  and  shape,  usually  somewhat  eccentrically  situated  in 
the  protoplasm  which  composes  the  body  of  the  cell.  It 
may  be  recognised,  as  a  rule,  by  its  comparative  opacity,  and 
is  made  more  visible  under  the  microscope  by  the  addition 
of  various  chemical  reagents,  dilute  acids,  etc. 

The  essential  value  of  the  nucleus,  according  to  Kolliker, 
who  takes  a  middle  ground  between  the  older  advocates  of 
the  cell  with  all  its  parts,  and  the  more  modern  advocates  of 
the  protoplasm  theory,  is  "to  secure  to  the  protoplasm  a 
definite  form  and  function,  and  more  especially  to  officiate 
as  its  proper  organ  of  reproduction."  The  ovum,  or 
primordial  cell  loses  its  nucleus,  as  one  of  the  first  signs  of 
development,  while  the  new  nucleus,  developed  later  in  the 


THE    CELL    CONTENTS  OR  PROTOPLASM.  113 

egg,  is  an  entirely  new  formation.  As  to  the  spermatozoid, 
it  is  wholly  and  exclusively  composed  of  the  nucleus  of  a 
cell,  the  remaining  constituents  of  which  have  been  left  be- 
hind it  in  the  seminal  ducts. 

The  nucleolus  is  the  still  more  minute  body  disposed  to- 
wards the  nucleus  and  acting  for  it  the  same  part  as  the 
nucleus  towards  the  entire  cell.  Both  of  these  bodies  are 
to  be  regarded  as  masses  of  protoplasm  differentiated  from 
the  main  mass  or  developing  within  the  main  mass  as  the 
youngest  or  latest  additions  of  matter.  When  staining 
matters,  carmine,  aniline,  etc.,.  are  brought  into  contact 
with  the  entire  cell,  the  newest  matter  is  deepest  stained. 
The  cell  wall  and  the  protoplasm  just  about  it  are  not  stained 
at  all. 

The   Cell    Contents    or  Protoplasm. 

If,  then,  the  cell  wall  be  relegated  chiefly  to  a  protective 
office,  and  the  nucleus  (with  its  contents)  to  the  function 
chiefly  of  reproduction,  it  is  in  the  cell  contents,  the  proto- 
plasm, that  we  must  locate  the  remaining  essential  pro- 
cesses in  the  life  of  the  cell.  The  lowest  forms  of  life  con- 
sist of  protoplasm  alone,  protoplasm  in  shapeless  mass, 
without  nucleus  or  wall.  Such  are  the  vast  masses  of 
gelatinous  matter  (deep  sea  ooze)  endowed  with  motion, 
assimilation,  reproduction,  etc.,  which  have  been  dredged 
(Huxley,  Thompson,  1868)  from  the  bottom  of  the  North 
Atlantic  Ocean,  at  depths  varying  from  5,000  to  25,000 
feet.  Much  doubt  has  been  cast  upon  the  nature  of  this  so- 
called  Bathybius  (  Urschleim),  by  the  fact  that  deep  ooze 
has  been  dredged  from  other  seas  not  endowed  with  these 
phenomena,  but  the  later  observations  of  Bessels  (1873) 
confirm  the  existence,  at  the  bottom  of  certain  seas,  of 
masses  of  pure  protoplasm,  "very  sticky,  mesh-like  struc- 
tures, with  perfect  amoeboid  movements,"  which  "took  up 

10 


114  THE  AMCE3A. 

particles  of  carmine  and    other  foreign    substances"    and 
which  "showed  active  motion  of  the  nuclei." 

The  Amoeba. 

Of  the  isolated  masses  of  protoplasm,  the  best  known  ex- 
ample is  the  amoeba.  Towards  the  close  of  the  last  century, 
O.  F.  Muller  gave  the  name  of  Proteus  to  certain  forms  of 
infusoria  observed  to  be  in  ceaseless  motion,  and  M.  Borg 
de  St.  Vincent  called  one  of  these  forms  (the  proteus 
diffluens),  "Amiba"  a  name  subsequently  changed  by 
Ehrenberg,  to  harmonise  it  with  his  etymology,  to  Amoeba" 
(Milne  Edwards).  Amoebae  are  masses  of  protoplasm  which, 
as  a  rule,  have  nuclei  but  no  walls,  but  since  Max  Schultze 
discovered  in  the  Adriatic  sea  a  non-nucleated  amoeba  (the 
amoeba  porrecta)  this  low  form  of  life  has  been  selected  from 
among  all  the  rest  as  a  basis  for  physiological  study. 

The  physiologist  has  here,  and  in  similar  structures,  a  case 
"in  which  those  vital  operations  which  he  is  elsewhere 
accustomed  to  see  carried  on  by  an  elaborate  apparatus,  are 
performed  without  any  special  instruments  whatever ;  a 
little  particle  of  apparently  homogeneous  jelly  changing 
itself  into  a  greater  variety  of  forms  than  the  fabled  Proteus, 
laying  hold  of  its  food  without  members,  swallowing  it  with- 
out a  mouth,  digesting  it  without  a  stomach,  appropriating 
its  nutritious  material  without  absorbent  vessels  or  a  circu- 
lating system,  moving  from  place  to  place  without  muscles, 
feeling  (if  it  has  any  power  to  do  so)  without  norves,  propa- 
gating itself  without  genital  apparatus.  And  not  only  this, 
but  in  many  instances  forming  shelly  coverings  of  a  sym- 
metry and  complexity  not  surpassed  by  those  of  any 
testaceous  animals"  (Carpenter). 

The  best  examples  of  protoplasm  devoid  of  walls  or  nucleus 
are  the  so-called  myxomycetes,  fungi  found  in  abundance 
on  decomposing  vegetable  matter,  moist  flower  pots,  bark 


THE  PROPERTIES  OF  PROTOPLASM.  115 

of  trees  after  a  rain,  etc.  The  best  examples  of  protoplasm 
with  wall  but  without  nucleus  are  the  hyphens,  fungi  found 
on  fruits,  bread,  etc.,  kept  in  a  warm  wet  place.  The  largest 
specimens  are  obtained  from  the  surface  of  manure  spread 
on  bricks  and  kept  in  moist  places.  Amoebae  are  the  best 
examples  of  protoplasm  with  nuclei  but  without  walls. 
These  animalcules  are  found  in  myriads  in  stagnant  wTater 
exposed  to  a  hot  sun.  Some  forms  of  amoebae  are,  as  we 
have  seen,  also  devoid  of  nuclei.  The  mammalian  ovum 
exhibits  the  typical  isolated  cell  with  all  its  parts,  nucleus, 
contents  and  wall.  It  may  be  readily  expressed  from  the 
ovary  after  puncture  of  the  Graafian  follicle. 

The  protoplasm  (-pu-og,  first,  tz/mcgu,  I  form),  or  cell  con- 
tents, constitutes,  thus,  the  essential  element  of  the  cell,  while 
the  wall  and  the  nucleus  are  to  be  regarded  as  additions  of 
structure  in  cells,  or  masses  of  protoplasm,  differentiated 
for  special  purposes  or  for  higher  grade  of  development. 
The  perfect  cell,  that  universally  present  in  the  construc- 
tion of  all  the  organs  of  animals  and  plants,  so  highly  de- 
veloped as  to  possess  organs,  consists  of  contents,  wall  and 
nucleus,  so  that  the  cell  with  all  its  parts  must  still  be  re- 
garded as  the  ultimate  physiological  element  in  the  body 
of  man. 

The  Properties  of  Protoplasm. 

In  studying  the  phenomena  of  life,  we  have,  therefore,  to 
consider  the  properties  of  protoplasm  as  observed  in  the 
forms  of  life  consisting  only  of  single  and  simple  masses  of 
protoplasm,  and  as  likewise  observed  in  more  complex  struc- 
tures composed  of  myriads  of  masses  (cells),  each  individual, 
independent,  and  in  a  sense  isolated,  yet  all  connected  and 
brought  into  harmonious  action  by  common  fluids  (blood, 
lymph,  etc.),  in  which  tjhey  are  continuously  bathed,  and 


116  SHE  PROPERTY   OF   MOTION". 

by  "facile  threads  of  communication,"  nerves,  bonds  and 
links  of  association. 

We  observe,  then,  first,  as  the  most  striking  endowment  of 
protoplasm, 

The  Property  of  Motion. 

Sarcode  (aapij,  flesh)  was  used  by  Dujardin  (1S35)  as  a 
synonym  of  protoplasm,  because  it  implied  the  property  of 
motion  as  observed  in  muscle  tissue.  This  motion  may  bo 
partial,  manifesting  itself  simply  as  a  protrusion  and  subse- 
quent retraction  of  some  portion  of  the  substance,  or  it  may, 
in  detached  and  isolated  masses,  be  general,  effecting  the 
locomotion  of  the  entire  mass.  The  amoeba,  for  instance, 
the  individual  mass  of  protoplasm,  extends  from  its  sub- 
stance prolongations  to  encircle  some  foreign  body,  the 
nutritive  principle  of  which  it  absorbs  and  incorporates,  to 
then  release  itself  or  flow  away  from  the  indigestible  residue. 
A  very  distinguished  botanist  was  once  deceived  into  the 
belief  that  a  starch  granule  had  become  converted  into 
living  protoplasm  by  observing  the  disappearance  of  the 
granule  and  its  substitution  by  a  moving  mass  of  matter ; 
the  apparent  substitution  being  only  an  envelopment  of  the 
granule,  for  the  time  being,  by  a  living  amoeba  in  its  vicinity. 
The  white  blood  corpuscle  may  thus  gradually  protrude 
itself  through  interstices  in  the  capillary  wall  to  effect 
migration  to  distant  parts. 

In  the  early  life  of  all  cells  (the  embryonal  stage  of  com- 
plex structures),  the  property  of  motion  is  always  manifest, 
but  as  the  cell  matures  or  becomes  senescent,  it  loses  this 
property  in  most  cases ;  it  becomes  quiescent  and  exhibits 
its  activity  only  in  other  ways. 

Individual  masses  of  protoplasm  being  invisible  to  the 
naked  eye  it  is  only  possible  to  study  their  motion  under 
the  microscope,  but  the  general  motion  effected  by  aggregate 


COLOR  CHANGES  IN   THE   CHAMELEON.  117 

masses  is  apparent  in  the  contractility  of  muscles,  locomo- 
tion of  members,  etc.  We  have  in  the  color  changes  assumed 
by  various  fishes  and  frog3  handsome  illustrations  of  the 
motion  of  cells.  The  change  of  color  is  effected  by  changes 
of  shape  in  cutaneous  pigment  cells.  The  colored  masses  of 
protoplasm,  (pigment  cells)  approach  to  or  withdraw  them- 
selves from  the  surface  and  thus  vary  the  color  of  the  ani- 
mal. If  the  pigment  cells  move  uniformly  in  the  skin,  the 
animal  is  uniformly  varied  in  color.  If  only  some  of  the 
cells  move,  the  animal  appears  spotted  or  striped  or  ringed, 
etc. 

The  Color  Changes  of  the  Chameleon. 

The  chameleon  is  so  universally  known  for  its  change- 
ability as  to  have  had  its  name  used  ever  since  Tertullian  as 
an  epithet  to  express  sycophancy  and  vacillation  of  purpose. 
Prior  says: — 

"As  the  chameleon  which  is  known 
To  have  no  colours  of  his  own 
But  borrows  from  his  neighbor's  hue 
His  white  or  black,  his  green  or  blue.'" 

And  Dryden  perpetuates  this  and  a  greater  fallacy  in  the 
lines : — 

"The  thin  chameleon  fed  with  air  receives 
The  colour  of  the  thing  to  which  he  cleaves." 

But  the  chameleon  is  not  so  changeable  as  has  been  repre- 
sented. It  is  not  able  to  assume  any  color  whatever,  nor  is 
it  able  to  take  on  the  color  of  every  object  upon  which  it 
may  rest.  Basking  in  the  sun  it  may  appear  blue,  green  or 
red,  according  to  the  incidence  of  the  light,  or  it  may  appear 
dark,  black  or  iridescent,  As  different  chameleons  differ  in 
the  natural  color  of  the  unpigmented  part  of  the  skin,  an 
individual  may  be  white  or  yellow.    Moreover  it  may  show 


118  COLOR  CIIAXGES  IX  THE  CHAMELEON. 

gray  and  brown.  All  these  colors  it  may  exhibit,  but  it 
may  not  exhibit  all  colors.  The  change  of  color  in  the 
chameleon  is  due  to  the  presence  in  the  skin  of  pigment 
cells  having  prolongations  which,  under  nervous  influence, 
may  penetrate  the  interstices  of  the  superjacent  layer  of 
unpigmented  skin  tissue,  and  spread  out  to  cover  the  surface 
wholly  or  in  part.  The  physical  laws  regulating  the  re- 
flection, absorption  and  interference  of  rays  of  light  in 
different  media  fully  explain  the  different  colors  the  animal 
may  assume.  What  especially  interests  us  in  this  connection 
is  the  property  of  motion  with  which  the  pigment  cells  are 
endowed,  and  which  enables  them,  in  obedience  to  stimulus 
from  the  nervous  system,  to  assume  different  shapes  and 
positions  with  reference  to  the  super  and  circumjacent  skin 
tissue  and  subjacent  blood-vessels.  When  a  chameleon  is 
poisoned  with  strychnia  it  becomes  uniformly  light  in 
color  from  a  complete  retraction  (tetanus)  of  the  pig- 
ment cells.  This  retraction  represents  the  active  con- 
dition of  the  cells.  When  the  animal  is  sick,  it  is 
spotted,  some  of  the  cells  being  retracted,  others  pro- 
truded. Section  of  individual  nerves  of  the  skin  produces 
the  same  effect,  corresponding  cells  being  passively  protruded 
(paralysed).  The  black  spots  now  show  dendritic  prolonga- 
tions. Section  of  a  series  of  nerves  produces  a  black  stripe. 
A  mechanical,  chemical  (turpentine)  or  electric  irritant 
applied  to  the  skin  induces  a  retraction  of  the  cells,  and 
thus  gives  rise  to  a  light  or  yellow  color  at  the  surface  of 
irritation.  The  cells  relax  and  spread  themselves  out 
(passively)  under  the  light  and  heat  of  the  sun,  hence,  the 
animal  under  such  conditions  is  dark  or  black.  In  dark- 
ness the  cells  are  actively  retracted,  hence,  the  animal  is  pale. 
If  parts  of  the  body  be  protected  from  the  sun,  as  by  bands 
of  varnish,  these  parts  remain  light,  while  the  rest  of  the 
body  is  dark.     Psychical  influences  likewise  affect  its  color. 


CILIARY  MOTION.  119 

In  the  passive  state  it  is  uniform  in  hue ;  excited  after 
food,  in  strife,  etc.,  it  is  variously  tinted.  Thus  "so  far 
from  being  a  symbol  of  falsehood,  the  chameleon  is  rather 
a  symbol  of  frankness,  as  every  emotion  is  depicted  upon 
its  surface"  (Briicke). 

But  the  motion  of  pigment  cells  is  not  independent. 
It  is  directly  under  the  control  of  the  nervous  system. 
The  motion  of  muscular  tissue,  though  inherent  in  the 
muscle  protoplasm  itself  is  evoked  by  the  nervous  system. 
Of  course,  in  speaking  of  independent  motion,  it  is  not  for 
a  moment  intended  to  imply  a  spontaneous  motion.  It  is 
simply  meant  that  we  are  ignorant  as  yet  of  the  external 
influences  which  induce  the  motion.  As  Strieker  has 
observed,  we  no  longer  term  the  movements  of  striated 
muscle  spontaneous,  because  we  know  the  external  influences 
or  stimuli  through  which  it  can  be  excited.  "And  so,  also, 
there  can  be  no  doubt  that  as  soon  as  we  have  acquired 
a  knowledge  of  all  the  external  influences  by  which 
movements  in  protoplasm  can  be  induced,  we  shall  cease  to 
term  them  spontaneous.  Thus,  in  stating  that  protoplasm 
is  capable  of  active  or  vital  (spontaneous)  movements,  we 
have  by  no  means  admitted  the  existence  of  an  immaterial 
force"  (Strieker).  The  best  example  of  protoplasmic  motion 
entirely  independent  of  the  nerves,  is  that  exhibited  in  the 
undulations  of  the  ciliary  processes  upon  the  surface  of  cer- 
tain epithelial  cells. 

Ciliary  Motion. 

Ciliated  epithelial  cells  are  cylindrical,  conoidal  or  goblet 
shaped  masses  of  protoplasm,  from  whose  upper  free  surface 
protrudes  a  thicket  (not  simply  a  few,  as  always  represented) 
of  fine,  hair  like,  processes,  the  cilia.  Such  structures  have 
long  been  recognised  in  certain  infusoria,  for  which  they 
furnish  means  for  locomotion,  prehension  of    food,  and 


120  CILIARY  MOTION. 

for  which,  also,  by  creating  currents,  they  minister  directly 
to  respiration.  Purkinje  and  Valentin  discovered  their 
existence  in  vertebrate  animals  and  in  man.  Such  cells 
line  the  entire  respiratory  tract  from  the  nasal  cavities, 
except  the  space  within  the  anterior  nares,  down  to  the 
finest  bronchioles  (but  not  the  air  cells).  Ciliated  cells 
tapestry  also  the  cavities  accessory  to  the  nasal,  the  antrum 
of  Ilighmore,  the  frontal  sinus,  etc.,  the  Eustachian  tube, 
and  for  the  most  part,  the  cavity  of  the  drum  of  the  ear. 
A  tract  of  epithelial  cells  is  also  found  in  the  epidydimus, 
the  efferent  ducts  of  the  testicles,  and  in  the  female,  in  the 
parovarium,  the  Fallopian  tubes,  and  the  body  of  the 
uterus,  extending  into  the  uticular  glands.  Ciliated  cells, 
though  much  smaller  and  more  delicate,  occur  also  in  the 
various  cavities  of  the  nervous  system ;  in  the  lateral 
ventricles,  the  floor  of  the  fourth  ventricle,  and  the  cerftral 
canal  of  the  spinal  cord. 

The  cilia  (cilium,  an  eyelash),  are  for  the  most  part  sabre 
shaped,  with  a  broad  attached  base  and  a  free  pointed 
extremity.  They  are  implanted  directly  into  the  protoplasm 
(the  cell),  of  which  they  are  part,  and  not  inserted  into  a 
membrane  or  an  upper  distinct  layer  of  protoplasm  as  once 
believed.  At  rest  they  are  slightly  inclined,  mostly  towards 
the  exterior  of  the  tube  or  cavity  in  which  they  are  found. 
In  motion  they  strike  with  their  broad  or  flat  surface  and 
return,  like  oars  in  skillful  hands,  by  feathering  the  edge, 
to  nearly,  but  not  quite,  a  perpendicular  position.  The 
stroke  is  the  result  of  an  active  contraction  (motion)  of  the 
protoplasm  while  the  less  quick  return  is  due  to  a  simple 
passive  elasticity.  But  the  cilium  in  its  stroke  is  not 
passively  moved  by  the  contracting  protoplasm.  On  the 
contrary,  it  is  the  cilium  itself  which  is  endowed  with  the 
contractility,  and  the  cell  when  free  (as  in  the  detached 
masses  found    in    the  secretion  of    coryza),   is    passively 


CONDITIONS  INFLUENCING   CILIARY   MOTION.  121 

moved  about  by  its  vibratile  cilia.  This  contraction  and 
relaxation  is  exceedingly  rapid,  too  rapid,  indeed,  to  be 
individually  visible.  Cilia  move  in  the  frog  at  the  rate  of 
twelve  times  in  the  second,  and  in  warm  blooded  animals 
much  faster.  It  is  only  when  contractility  has  become 
partially  exhausted  that  individual  motion  may  be  observed. 
In  molluscs,  where  the  cilia  are  of  very  great  size,  their 
motion  produces  undulations  which  may  be  seen  in  its 
totality  as  glittering  waves  even  by  the  naked  eye.  The 
motion  of  tracts  of  cilia  has  been  not  inaptly  compared  to 
the  undulations  of  a  field  of  grain  agitated  by  the  wind, 
or  to  the  glistening  of  a  river  in  the  sun. 

Conditions  Influencing  Ciliary  Motion. 

Cilia  are  entirely  independent  of  the  nervous  system. 
Section  or  stimulation  of-  nerves  produces  upon  them  no 
effect.  They  contract  when  removed  from  the  body,  and 
survive  somatic  death  for  hours,  even  nine  hours  in  the 
frog.  Nevertheless  ciliary  motion  in  life  is  not  irregular ; 
all  the  cilia  in  a  given  "tract  move  in  a  definite  direction, 
and  produce  definite  currents  in  the  circumambient  fluids. 
It  is  for  this  reason  that  particles  of  mucus  or  other  for- 
eign bodies  are  propelled  upon  the  surface,  tossed  from 
place  to  place,  towards  the  exterior.  The  force  of  cilia  is 
really  astonishing.  Particles  of  coal  dust  suspended  over 
them  by  means  of  a  drawn  thread  of  sealing  wax  are  lifted 
and  pushed  on  at  the  rate  of  -^^  of  an  inch  per  second. 
It  was  by  means  of  such  an  experiment  that  Kistiackowsky 
was  able  to  prove  that  induced  currents  of  electricity 
stimulated  the  cilia,  contrary  to  opinions  expressed  hitherto, 
to  greater  activity,  or  renewed  it  after  a  period  of  quies- 
cence. Heat  quickens,  cold  retards  their  motion.  The 
activity  of  the  movements  of  protoplasm  in  general  is 
greatest  at  about  100°  F.  (38°  C).    At  32°  F.  (0°  C),  they 


122  MOTION   OF   OTHER   CELLS. 

become  extremely  sluggish,  or  ceases  altogether.  The  ova 
of  trout,  however,  uudergo  segmentation  perfectly  in  iced 
water,  whilst  they  soon  cease  to  move  at  ordinary  tempera- 
tures. Dilute  alkalies  act  as  ^direct  stimulants  to  ciliary 
motion,  partly  by  simply  diluting  the  thickening  mucus  in 
which  they  float  and  partly  by  increasing  oxidation.  Chlo- 
roform suspends  their  activity,  or  in  excess  disorganises  and 
destroys  the  cells. 

Ciliated  epithelial  cells  are  best  obtained  for  study  by 
scraping  the  roof  of  the  mouth  or  the  pharynx  of  the  frog. 
A  few  cells  may  be  detached  in  man  by  inserting  a  feather 
into  the  upper  cavities  of  the  nose.  The  largest  cilia  are 
found  in  the  molluscs,  in  the  so-called  beard  of  the  oyster  or 
clam.  Tracts  of  cells  are  secured  by  dissecting  off  parts  of 
the  pharyngeal  mucous  membrane  of  the  frog.  Calliburces 
constructed  a  very  elegant  apparatus  to  cause  cilia  in  motion 
to  strike  upon  and  revolve  a  glass  cylinder  and  thus  record 
their  own  velocity  of  movement.  Bowditch  exhibited  this 
motion  more  simply  and  effectually  by  cutting  through  the 
body  of  a  frog  just  below  its  anterior  extremities,  after 
destruction  of  the  spinal  cord,  and  passing  a  glass  rod 
through  the  oesophagus.  The  body  of  the  frog  is  gradually 
pushed  along  the  rod  by  the  motion  of  the  oesophageal  cilia. 
The  front  part  of  the  jaws  should  be  cut  away  to  prevent 
too  great  friction,  and  the  rod  should  be  dipped  in  salt  water 
to  secure  the  best  action  of  the  cilia.  If  the  oesophagus 
alone  be  slipped  over  the  tube  the  motion  will  be  much 
more  apparent. 

Motion  of  Other  Cells. 

A  spermatozoid  is  a  detached  ciliated  cell ;  the  whip-lash 
tail  is  the  cilum  and  the  head  is  the  nucleus  of  the  cell. 
The  spermatozoid,  all  moving  protoplasm,  indeed,  is  affected 


MOLECULAR   MOVEMENTS,,  123 

in  like  manner  with  ciliated  epithelium  by  the  various 
agents  mentioned. 

Motion  has  been  studied  also  in  the  lymph  and  pus  cor- 
puscles, in  cartilage  and  in  connective  tissue  cells.  Certain 
corneal  corpuscles  have  been  observed  by  Recklinghausen 
to  penetrate  tissue  interstices  and  wander  about,  like  the 
white  blood  corpuscles,  to  considerable  distances.  It  is  by 
means  of  motion  of  this  kind  that  young  cells  may  arrange 
themselves  in  position  in  the  original  construction  of  the 
various  tissues  and  organs 

But  the  motion  of  the  highest  physiological  interest  in 
this  connection  is  that  which  takes  place  in  the  interior  of 
the  cell  itself.     Such  movements  are  known  as 

Molecular  Movements, 

because  they  consist  of  agitations,  tremblings  or  rotations 
of  the  fine  granules  in  the  protoplasmic  mass.  These 
movements  are  not  to  be  confounded  with  those  exhibited 
by  inorganic  bodies  floating  free  in  fine  particles,  the 
movement  described  by  Brown,  and  known  as  the  Brunonian 
movements,  for  in  the  case  of  the  inorganic  body  the 
movements  are  oscillatory  or  merely  passive  folio  wings  of 
the  currents  in  the  fluids.  Protoplasmic  molecular  move- 
ment is  active  and  translative  from  place  to  place.  It  may  be 
seen  to  advantage  in  the  cells  of  the  salivary  glands,  in  living 
blood  corpuscles  (white)  or  in  pus  corpuscles  when  water  is 
added  to  the  fluid  in  which  they  float.  These  movements  cease 
only  with  the  death  of  the  cell.  A  stroke  of  electricity 
which  kills  the  cell  stops  the  granular  movement  at  once, 
proof  that  it  is  in  no  sense  a  passive  phenomenon.  The  hair 
of  the  stinging  nettle  exhibits  protoplasmic  molecular  move- 
ment even  more  clearly  than  any  animal  structure.  Such  a 
hair  consists  of  one  elongated  cell  filled  with  intra-cellular 
fluid ;  its  transparent  wall  being  lined  with  soft  protoplasm. 


124  MOLECULAR  CHANGES  IN  THE  OVUM. 

The  molecules  or  granules  in  the  protoplasm  not  only  trem- 
ble like  the  salivary  corpuscles,  but  they  actually  circulate 
in  a  regular  stream.  The  protoplasm  itself  undulates  in 
different  directions.  A  shock  from  a  magnetic  electro- 
motor apparatus  arrests  the  regular  system  of  waves,  and 
suddenly  projects  the  protoplasm  in  promontories  into  the 
intra-cellular  space.  During  this  attack,  so  to  speak,  the 
molecular  motion  ceases,  to  recur  only  when  the  protoplasm 
resumes  its  normal  motion. 

Molecular    Changes  in   the  Ovum. 

The  ovum,  or  primordial  cell,  is,  however,  here  again,  the 
best  object  for  study  of  this  kind  of  motion.  The  ovum  in 
both  plants  and  animals  is  the  continual  seat  of  molecular 
motions  of  the  most  active  as  well  as  curious  character.  In 
its  development  the  nucleus  of  the  ovum  first  becomes 
elongated,  spindle-shaped  and  covered  with  fine  threads  or 
hairs.  The  granules  of  the  protoplasm  now  move  about  to 
arrange  themselves  in  regular  lines  irradiating  from  the 
ends  of  the  nucleus  and  finally  the  whole  protoplasm  splits 
in  two,  forming  two  cells,  a  smaller,  so-called  cemetery-cell, 
containing  the  products  of  excretion,  which  entirely  disap- 
pears, and  a  larger  formative  cell  which  contains  all  the 
elements  essential  to  the  formation  of  the  new  being.  In 
ova  without  special  walls,  enveloped  only  in  the  mucus 
from  the  maternal  genital  canals,  a  single  spermatozoid,  out 
of  the  70-80  upon  the  surface  of  the  enveloping  mucus,  pene- 
trates the  mucus  to  reach  the  yolk.  "At  the  moment  when 
this  penetration  is  effected,  the  yolk,  which  had  hitherto 
presented  a  uniform  arched  surface,  suddenly  projects  an 
elevation  towards  the  head  of  the  spermatozoid,  seizes  it, 
surrounds  it  and  draws  it  with  a  celerity  which  almost 
escapes  vision,  into  the  interior  of  the  egg."  The  tail  of  the 
spermatozoid  now  disappears  by  solution  in  the  yolk  proto- 


MOLECULAR  CHANGES  IN  THE  OVUM.  125 

plasm,  and  the  head  gradually  travels  towards  the  nucleus 
of  the  ovum.  So  soon  as  contact  is  effected  the  two  bodies 
roll  about  each  other  several  times  and  then  fuse  together 
to  become  the  new  nucleus  of  the  ovum.  Hereupon  ensues 
the  division  and  subdivision  of  the  new  nucleus,  until  the 
whole  ovum  has  undergone  the  process  of  segmentation  into 
daughter  cells,  which  arrange  themselves  into  three  layers, 
the  blastodermic  layers,  containing  the  elements  of  construc- 
tion of  the  whole  body.  In  ova  provided  with  a  distinct 
wall  (zona  pellucida)  there  may  be  usually  detected  some- 
where in  the  wall  a  large  opening,  the  micropyle,  for  the 
entrance  of  the  spermatozoid.  The  cell  wall  is  often  pene- 
trated, besides,  by  very  fine  radiating  canals,  in  every  one  of 
which  is  a  thorn-like  protrusion  of  the  yolk  stopping  up  the 
canals,  like  bottle  stoppers,  to  prevent  the  entrance  of  fluids 
in  which  all  ova  float.  A  cord  or  track  of  clear  protoplasm, 
the  so-called  seminal  cord,  passes  from  the  micropyle  to  the 
nucleus  of  the  ovum,  as  a  road  along  which  the  spermatozoid 
may  pass  to  the  nucleus  of  the  ovum. 

Now  the  most  serious  accident  that  can  befall  an  ovum  is 
the  accidental  penetration  of  more  than  one  spermatozoid. 
Malformations  and  double  monstrosities  always  occur  after 
such  accidents.  But  the  ovum  is  protected  against  these 
accidents  by  a  provision  which  is  as  curious  as  effective,  and, 
as  a  striking  exemplification  of  molecular  motion,  is  worthy 
of  mention  here.  In  the  naked  (wall-less)  cells,  at  the 
moment  when  the  hillock  of  yolk  has  seized  upon  the  first 
penetrated  spermatozoid,  "a  fine,  delicate,  but  very  resistent 
membrane  immediately — so  quickly  as  to  be  invisible  to 
the  eye.  in  its  stages  of  formation,  a  kind,  therefore,  of 
chemical  deposit — covers  over  the  whole  surface  of  the 
yolk,"  to  effectually  bar  the  passage  of  further  spermato- 
zoids.  In  ova  with  walls,  a  number  of  spermatozoids  are 
seen  gliding,  head  first,   about  the  surface  of  the  wall. 


126  MOTION   THE  ESSENCE   OF    REPRODUCTION. 

Finally,  one  succeeds  in  reaching  the  micropyle.  "So  soon 
as  this  happens,  the  seminal  cord  is  at  once  torn  away  from 
the  micropyle  and  the  thorn-like  protrusions  of  the  yolk  are 
at  once  withdrawn  from  the  radiating  canals  in  the  zona 
pellucida,  whereupon  water  streams  into  the  radiating 
canals  and  through  the  open  micropyle,  to  spread  out 
between  the  surface  of  the  yolk  and  the  zona  pellucida. 
The  zona  pellucida  (cell  wall)  is  thus  lifted'  away  from  the 
yolk  (cell  contents)  and  thrown  into  irregular  folds  to 
oppose  an  insurmountable  obstacle  to  the  penetration  of 
even  a  second  spermatozoid"  (Lowe). 

The  motion  of  the  molecules  in  the  ovum  is  the  cause  of 
its  development.     That  is,  motion  is  the 

Essence  of   Reproduction. 

The  assistance  of  the  male  element  is  not  by  any  means  a 
necessity  in  reproduction.  In  many  animals,  notably  in  in- 
sects, continued  progeny  (ten  to  twelve  generations)  is  pro- 
duced without  copulation.  Generation  of  this  kind, 
partheno -genesis,  or  virgin  generation,  instead  of  being  a 
mysterious  exception,  is  the  rule  in  all  animals  up  to  a  cer- 
tain grade  of  development.  Bischoff  found  that  all  the  first 
stages  of  development,  disappearance  of  the  germinal 
vesicle,  appearance  of  the  new  nucleus  in  the  interior  of  the 
yolk,  condensation  and  volume  reduction  of  the  yolk,  move- 
ment phenomena  in  the  yolk,  finally  even  the  first  stages  of 
segmentation,  all  these  changes  occur  in  eggs  which  have 
never  been  impregnated,  and  in  eggs  which  are  never 
impregnated  at  all,  but  which  have  been  discharged  from 
the  ovary  simply  on  account  of  their  maturation.  Moquin 
Tandon  has  seen  the  process  of  segmentation  of  the  yolk  in 
unimpregnated  frog's  eggs,  and  Van  Beneden  has  shown 
that  the  first  phases  of  development  in  the  rabbit  are 
entirely  independent  of  impregnation.    These  changes  are 


PARTHENOGENESIS  127 

not  dependent,  therefore,  upon  the  formal  union  and  copu- 
lation of  a  sperm  and  germ  cell,  nor  upon  any  chemical  or 
dynamical  effect  of  the  spermatozoids,  for  they  occur  with- 
out the  presence  of  spermatozoids  at  all.  They  depend 
upon  the  motion  inherent  in  the  molecules  of  the  ovum 
itself.  But,  in  the  rule,  we  observe  that  the  intensity  of  this 
motion  is  not  sufficiently  great  to  lead  to  further  develop- 
ment and  production  of  form.  It  must  receive  additional 
force,  and  probably  also  a  definite  direction,  in  order  that 
the  further  movements  of  development,  those  requisite  to 
the  complete  construction  of  the  embryo,  may  ensue.  The 
egg  receives  this  further  addition,  strength  and  direction  of 
motion  from  the  spermatozoids,  whose  individual  mass 
movement  is  proof  that  the  matter  of  their  composition  is 
also  in  the  condition  of  intense  activity.  Bischoff  in 
making  this  statement  concludes :  "we  possess  nowhere  else 
such  a  perfect  insight  into  the  cause  of  organic  movements  as 
here,  and  the  view  which  this  insight  gives  will  be  as  satis- 
factory to  the  reasoning  mind  as  every  other  application  of 
the  law  of  the  conservation  of  force." 

The  case  of  the  bee  affords  a  striking  confirmation  of  the 
fact  that  development  up  to  a  certain  grade  is  possible 
without  copulation,  while  more  perfect  development  re- 
quires assistance.  Thus  the  queen, bee  in  captivity  or  isola- 
tion continues  to  breed  drones  (males)  almost  indefinitely, 
and  under  conditions  which  preclude  the  idea  of  any  utilisa- 
tion of  sperm  stored  up  in  the  past,  while  the  produc- 
tion of  workers  (females)  only  ensues  after  copulation.  In 
fact,  the  observations  of  Leuckart  and  Siebold  prove  that 
spermatozoids  are  always  found  about  the  micropyle  of  the 
ova  of  females,  and  never  about  the  ova  of  males.  But 
among'the  sack  bearing  insects  (psychides)  the  sex  is  reversed, 
that  is,  the  production  of  males  requires  copulation  ( Wundt). 

The  essence  of  reproduction,  therefore,  so  far  as  may  be 


128  THE  CIIEMISTTIY   OF  PROTOPLASM. 

comprehended  by  the  limited  understanding  of  man,  is  a 
transmission  of  motion,  as  the  remaining  manifestations  of 
protoplasm  (the  various  phenomena  of  life),  are  transmuta- 
tions of  some  physical  force. 


LECTUKE    VII. 


PROTOPLASM  AND  ITS  PROPERTIES. 

CONTENTS. 

The  Chemistry  of  Organic  Matter— The  Ultimate  Elements— The 
Proximate  Principles — Albumen  and  its  Products — The  Chemistry 
of  the  Cell — Absorption  and  Assimilation — Metabolism — Oxidation 
Processes — Oxidation  in  the  Ovum — Oxidation  in  Muscle — Oxidation 
in  the  Blood — Oxidation  in  Nerve  Tissue — The  Quantity  of  Oxygen 
in  the  Body — The  Genesis  of  Protoplasm — Spontaneous  Generation— 
Omne  Yivum  ex  Ovo — Reproduction  and  Nutrition — Modes  of  Cell 
Genesis — Death  of  Cells — Recapitulation — Classifications  of  the 
Tissues. 

We  have  already  regarded  the  matter  of  the  body,  the 
protoplasm,  from  an  anatomical  stand-point  and  before  con- 
tinuing the  study  of  its  properties  we  shall  have  to  survey 
it  from  a  chemical  point  of  view. 

What  seems  especially  striking  in  the 

Chemical  Analysis  of  Organic  Matter 

is  the  simplicity  of  its  elementary  construction.  The  num- 
ber of  elements  entering  into  its  composition  we  discover  to 
be  extremely  small.  Of  the  sixty-four  ultimate  elements 
into  which  the  matter  of  our  earth  may  be  resolved  but  four 
take  any  prominent  part  in  the  manufacture,  so  to  speak, 
of  purely  organic  matter.     These  are  carbon,  which  is  absent 


THE  ritOXIMATE  miNCirLES.  129 

in  no  organic  body,  and  oxygen,  hydrogen  and  nitrogen. 
But  in  the  construction  of  the  more  complex  animal  and 
vegetable  bodies  we  encounter  also  seven  other  elements, 
viz.,  sulphur,  phosphorus  and  iron,  as  elements  most  widely 
diffused,  and  chlorine,  potassium,  sodium  and  calcium  as 
elements  most  rarely  met.  The  first  four  mentioned  ele- 
ments, carbon,  oxygen,  hydrogen  and  nitrogen,  are  the 
essential  elements;  the  rest  are  said  to  be  incidental  ele- 
ments. I  have  here  before  me  a  glass  of  water.  I  drop  into 
it  a  small  piece  of  coal.  We  have  now  in  this  glass  hy- 
drogen and  oxygen  in  the  water,  nitrogen  (with  oxygen)  in 
the  air  and  carbon  in  the  coal,  all  the  essential  elements, 
and  in  some  cases  the  only  elements,  entering  into  the  com- 
position of  organic  matter. 

The  Proximate  Principles. 

But  no  familiarity  with  the  characters  or  properties  of 
these  ultimate  elements  may  acquaint  us  with  the  properties 
of  their  compounds,  the  results  of  their  combinations,  the 
so-called  proximate  principles,  as  they  are  encountered  in 
the  body.  No  knowledge,  for  instance,  of  the  peculiarities 
and  characteristics  of  chlorine,  a  heavy,  greenish-colored 
gas,  with  bleaching  properties,  or  of  sodium,  a  whitish 
mineral  which  burns  upon  the  surface  of  water,  would  in- 
form us  as  to  the  properties  and  characteristics  of  the 
chloride  of  sodium  (common  salt),  a  substance  as  different 
from  either  of  the  elements  of  which  it  is  composed  as  they 
are  from  each  other.  In  the  study  of  the  structure  of  the 
body  from  a  chemical  point  of  view,  it  is  the  combinations 
of  the  elements,  and  not  the  elements  themselves,  with 
which  we  have  to  deal ;  the  proximate  principles,  and  not 
the  ultimate  elements,  present  the  peculiarities  pertaining 
to  living  things. 

There  are  organic  compounds  which  consist  of  but  two  of 


130  ALBUMEN  AND  ITS  PRODUCTS. 

these  ultimate  elements,  but  the  great  majority  of  them  are 
made  up  of  three,  viz :  carbon,  hydrogen  and  oxygen.  These 
carbo-hydrates  owe  their  name  to  the  fact  that  they  are 
composed  of,  besides  carbon,  hydrogen  and  oxygen,  in  the 
proportion  to  form  water.  Starch  and  the  various  sugars, 
so  easily  mutually  convertible  by  the  addition  or  abstraction 
of  water,  are  examples  of  the  carbo-hydrates.  The  closely 
allied  fats  have  an  excess  of  hydrogen,  so  that  all  these  sub- 
stances are  often  grouped  under  the  head  of  the  hydro- 
carbonaceous  compounds. 

Another  group  of  organic  matters  contains,  in  addition 
to  the  three  elements  mentioned,  nitrogen.  They  are,  there- 
fore, known  as  the  nitrogenous  in  distinction  to  the  non- 
nitrogenous  principles.  To  this  group  belong  the  complex 
products,  the  albumenoids  (including  haemoglobin  and 
vitellin),  which  also  contain  sulphur,  phosphorus  or  iron. 
The  white  of  egg  is  a  typical  albumenoid  substance. 

Chemical  analysis  of  the  body  discloses,  besides  these  two 
classes  of  principles,  the  nitrogenous  and  non-nitrogenous,  a 
third  group  of  inorganic  or  mineral  principles,  as  water, 
common  salt,  phosphate  of  lime,  etc.,  contributing  to  the 
formation  of  tissues  and  juices  of  every  character  and  con- 
sistence. 

Albumen  and  its  Products. 

The  chief  constituent  of  protoplasm  is  albumen  in  some 
one  or  other  of  its  numerous  forms.  Albumen  with  water 
in  considerable  amount,  mineral  matters  and  fat,  these  are 
the  substances  which  compose  the  animal  cell.  Protoplasm 
is  thus  a  peculiar  albuminous  compound,  tough  and  viscid 
before  undergoing  subsequent  change,  which  coagulates 
under  heat  (or  at  the  death  of  the  cell,  as  in  rigor  mortis), 
and  which  is  swollen  up  or  gelatinised,  but  is  not  dissolved, 
by  the  action  of  water. 


THE  CHEMISTRY  OF  THE  CELL.  131 

It  is  a  humiliating  confession  to  have  to  make,  but  it  is 
true,  as  Frey  remarks:  "This  is  about  all  we  know,  at  pres- 
ent, of  this  important  compound,  protoplasm." 

We  recognize  in  albumen,  in  some  of  its  forms,  the  funda- 
mental substance  in  the  composition  of  protoplasm.  In  the 
lowest  forms  of  life,  at  all  times,  and  in  the  higher  forms  in 
the  embryonic  stage,  albumenoid  (protein)  bodies  are  uni- 
versally present.  But  as  development  advances  in  the  more 
complex  forms  the  differentiation  of  individual  masses  of 
protoplasm  into  separate  tissues  and  organs  is  characterized 
by  a  change  of  the  protein  bodies  into  some  of  their  more 
permanent  derivatives,  as  chondrin,  elasticin,  etc.  What 
especially  characterizes  the  albumenoid  bodies  is  their  insta- 
bility of  structure,  that  is,  the  readiness  with  which  they 
may  be  broken  up  into  new  compounds.  In  this  decomposi- 
tion, the  force  latent  in  the  albumen  is  translated  into  active 
forms  with  the  development  of  various  decomposition  pro- 
ducts wThich  escape  in  the  secretions.  Such  products  are 
urea,  leucin,  tyrosin,  creatin,  creatinin,  glycogen,  peptones, 
and  ferments.  Some  of  these  products,  glycogen,  peptones, 
etc.,  are  true  secretions,  having  further  purpose  to  subserve 
in  the  body ;  others,  urea,  creatin,  creatinin,  are  veritable 
excretions,  effete  matters  of  no  further  use.  Very  grossly 
considered,  the  first  mentioned  useful  products  correspond 
to  the  steam  of  the  engine;  they  are  the  agents  of  force ; 
while  the  seqond  class  of  useless  products  are  the  ashes  and 
smoke  ;  they*  must  escape  from  the  body,  as  their  accumula- 
tion in  it  extinguishes  the  processes  of  life. 

The  Chemistry  of  the  Cell. 

The  protoplasm  (or  cell  contents)  is  thus  composed  of 
albumen  in  some  of  its  forms,  of  water,  of  mineral  matter 
and  of  fat.  The  outside  or  cortical  layer  of  protoplasm 
(the  cell),  when  such  a  layer  is  present,  differs  from  the 


132  ABSORPTION  AND  ASSIMILATION. 

inner  substance  in  its  greater  density.  The  albumen  is  here 
converted  (differentiated)  into  elasticin,  which,  as  its  name 
implies,  is  more  resistant  and  elastic,  and  hence  is  better 
qualified  to  serve  as  a  protection  to,  and  to  regulate  diffusion 
for,  the  more  delicate  protoplasm  inclosed. 

The  nucleus  of  the  cell,  again,  may  also  be  differentiated 
into  a  wall  and  more  fluid  contents  chemically  somewhat 
different,  in  turn,  from  the  wall  and  contents  of  the  main 
cell.  Thus  minute  granules  are  readily  precipitated  in  the 
nuclear  contents  by  the  addition  of  alcohol  and  acids,  while 
the  wall  of  the  cell  differs  from  that  of  the  nucleus  by  the 
greater  solubility  of  the  former  in  alkalies.  The  nucleolus, 
from  its  high  refracting  properties,  is  supposed  to  consist 
largely  of  fat. 

With  this  glance  at  the  chemical  constitution  of  the  cell 
we  are  better  prepared  to  continue  the  study  of  its  properties. 

Absorption  and  Assimilation. 

Cells  have  the  power  to  absorb,  assimilate  or  store  up 
material  from  without,  to  elaborate  or  transform  the  ma- 
terial thus  absorbed,  and  to  filter  out,  excrete  or  eject 
material  from  within. 

In  the  ordinary  growth  and  nutrition  of  the  cell  new 
matter  passes  by  penetration,  imbibition  or  osmosis,  directly 
into  the  substance  of  the  cell.  The  whole  collection  of  cells 
constituting  the  body  may  be  roughly  compared  to  a  sponge 
soaked  in  nutrient  fluids.  These  fluids  penetrate  the  wall, 
and  thus  constantly  contribute  to  the  cell  new  material. 
Just  as  every  plant  absorbs  from  the  earth  the  particular 
salts  essential  to  its  growth,  does  each  cell  drink  up  from  its 
earth,  the  blood  and  the  part  of  the  body  in  which  it  is 
found,  the  particular  elements  essential  to  its  growth  and 
work.  The  cell  in  this  way  feeds  itself,  absorbing  with 
what  seems  a  selective  agency  (chemical  affinity)  the  ma- 


TROCESSES  OF  OXIDATION.  133 

terial  upon  which  it  can  live  and  work,  and  with  some  dis- 
crimination refusing  to  absorb  useless  and  innutritious 
matter.  The  new  matter  may  then  be  transformed  into  the 
protoplasm  of  the  cell  (assimilated),  or  it  may  be  stored  up 
for  other  use  in  its  work.  Thus  the  protoplasm  grows,  im- 
perceptibly increases  in  size,  or  fills  itself  with  foreign 
bodies  (blood  corpuscles,  fat  cells,  coloring  matters),  which 
may  be  seen  entire  or  in  fragments  in  the  body  of  the  cell. 

The  Metabolism  of  the   Cell. 

The  transformation  of  matter  (metabolism)  in  the  in- 
terior of  the  cell,  is  the  highest  physiological  endowment 
of  protoplasm.  In  this  process,  chemical  changes,  to  large 
degree  inscrutable  as  yet,  are  incessantly  at  work.  Muscle- 
cells  and  nerve-cells  elaborate  in  this  way  their  irrita- 
bility and  other  properties  which  endow  them  with  their 
peculiar  physiological  dignity  as  the  master-tissues  of  the 
body.  Gland-cells  manufacture  ferments ;  as  the  gastric 
epithelium,  pepsin,  the  pancreas,  pancreatin,  or  new  com- 
pounds, as  the  mammary  cells,  milk  sugar,  liver  cells, 
glycogen;  from  the  disintegration  and  rearrangement  of 
matters  pre-existent  in  the  blood.  Lastly,  certain  masses 
of  protoplasm  (cells)  come  to  be  set  apart  for  the  pur- 
pose simply  of  filtering  out  from  the  blood  and  eliminating 
from  the  body  various  products  of  decomposition  and 
waste. 

The  most  important  factor  in  effecting  these  various 
metamorphoses  is  oxygen  gas.  To  great  extent  the  chemi- 
cal changes  in  the  cell,  the  metabolism  of  the  cell,  as  it  is 
called,  are 

Processes  of    Oxidation. 

The  various  excretions  of  the  animal  body  are,  as  we  have 
seen,  for  the  most  part,  products  of  oxidation.    Of  these 


134  OXIDATION   IN   THE   OVUM. 

excretions,  some,  carbonic  acid  gas  and  water,  are  com- 
pletely oxidised  products,  while  others,  the  urates,  for  in- 
stance (but  not  urea)  escape  only  partly  consumed  (oxidised) 
and  must  undergo  further  oxidation  outside  of  the  body 
before  they  are  resolved  into  the  fully  oxidised  products, 
water,  carbonic  acid  gas,  ammonia,  etc.  These  finally 
oxidised  products  thus  restore  to  the  earth  and  air  what 
was  abstracted  by  the  plant. 

"See  dying  vegetables  life  sustain, 
See  life  dissolving-  vegetate  again, 
All  forms  that  perish  other  forms  supply, 
By  turns  we  catch  the  vital  breath  and  die."        Pope. 

Oxidation  (union  with  oxygen),  so  far  as  we  can  follow 
it,  causes  the  decomposition  or  splitting  up  of  compound 
into  simple  bodies.  Deoxidation  (abstraction  of  oxygen) 
causes  or  attends  the  rearrangement  of  simple  into  com- 
pound bodies.  The  plant  (vegetable)  cell  has  the  power, 
under  the  light  and  heat  of  the  sun,  to  disengage  oxygen 
and  rearrange  the  atoms  of  simpler  into  more  compound 
bodies.  In  this  way  the  plant-cell  builds  up  and  stores 
up  these  compounds  as  latent  force.  The  animal  cell 
(protoplasm)  has  the  power  to  reduce  these  compounds, 
with  the  aid  of  oxygen,  and  set  the  latent  force  free. 

Oxygen  being  thus  the  principal  agent  in  decomposing 
the  matter  of  the  animal  cell,  and  setting  free  the  force 
which  it  contains,  we  may  now  consider  its  appropriation 
by  the  various  organs  somewhat  in  detail. 

Oxidation  in  the  Ovum. 

To  commence,  then,  at  the  beginning  of  the  cell,  it  is 
observed  that  the  ovum  breathes.  The  butt  end  of  the 
chicken's  egg  has  a  cavity  filled  with  air,  which,  according 
to  BischofF,  contains,  on  the  average,  23.  5  per  cent,  (more, 
thus,  than  the  atmosphere,  which  contains  but  20  per  cent.) 
of  oxygen  gas.    This  cavity  is  a  reservoir  of  air  for  extra 


OXIDATION   IN  MUSCLE.  135 

demands.  Oxygen  continually  penetrates  the  shell  of  the 
egg  in  greater  quantity  as  the  shell  grows  thinner,  in  corre- 
spondence, thus,  with  the  increasing  demands  of  increasing 
development  within. 

In  Baumgartner's  artificial  hatching  experiments,  so 
conducted  that  the  absorption  of  oxygen  and  exhalation 
of  carbonic  acid  gas  could  be  accurately  measured,  it  was 
observed  that  the  egg  gained  in  twenty  days  (up  to  the 
time  of  the  escape  of  the  young  chicken  from  its  cavity) 
26.82  per  cent,  in  weight;  a  gain  attended  with  the  ab- 
sorption of  6.29  per  cent,  of  oxygen,  and  the  escape  of 
8.412  per  cent,  of  carbonic  acid  gas,  and  24.69  per  cent, 
of  water.  The  volume  of  the  oxygen  absorbed  from  the 
air  is  always  greater  than  that  escaping  with  the  carbonic 
acid  gas,  as  the  oxygen  not  only  contributes  to  the  forma- 
tion of  carbonic  acid  gas  and  water,  but  is  also  used  in  the 
formation  of  other  products  remaining  in  the  substance  of 
the  egg. 

Though  there  are  many  recondite  chemical  processes 
continually  in  operation  in  the  body,  most  of  the  changes 
connected  with  the  development  of  force  are  simple  oxi- 
dations. The  force-material  of  the  body  may  be  said, 
therefore,  to  be  represented  by  oxidisable  (organic)  com- 
binations on  the  one  hand,  and  by  free  oxygen  on  the 
other. 

The  direct  absorption  of  oxygen  gas  has  been  observed 
by  Kuhne,  in  the  case  of  the  ciliated  epithelial  cells. 
The  movements  of  cilia  are  intimately  connected  with  the 
consumption  of  oxygen.  They  cease  in  its  absence,  and 
they  cannot  be  started  again  without  it. 

Oxidation  in  Muscle. 

The  contraction  of  muscle  protoplasm  is  as  closely  con- 
nected with  the  absorption  of  oxygen,  and  the  excretion 


136  OXIDATION   IN   THE  BLOOD. 

of  carbonic  acid  gas.  But  it  is  not  so  much  the  muscle 
substance  itself  that  is  oxidised  in  the  production  of  mus- 
cular force,  as  the  non-nitrogenous  elements  of  the  blood, 
circulating  through  the  muscle.  For,  it  has  been  now 
pretty  clearly  established  that  the  urea,  urates,  etc.,  pro- 
ducts of  the  waste  of  muscle  itself,  are  not  increased  in 
the  excretions  (urine)  in  correspondence  to  muscular  ex- 
ercise. On  the  contrary,  the  increase  concerns  the  car- 
bonic acid  gas  exhaled  from  the  lungs,  proof  that  it  is  the 
carbo-hydrates  of  the  food,  and  not  the  nitrogenous  mus- 
cle itself  which  serve  as  fuel  for  the  muscle  machinery. 
When  a  muscle  is  at  rest,  the  blood  in  its  emulgent  veins 
is  red  in  color,  but  after  contraction  its  escaping  blood 
is  deoxidised  to  a  blue  color,  showing  that  oxygen  is  used 
up  in  the  blood.  But  oxidation  of  muscle-substance  itself 
does  take  place,  in  some,  though  slight,  degree.  For,  aside 
from  the  presence  or  absence  of  its  products  in  the  urine, 
a  muscle  will  continue  to  give  off  carbonic  acid  gas  for  a 
time,  even  when  washed  free  of  blood,  or  even  when 
placed  in  an  atmosphere  absolutely  free  from  oxygen,  as  in 
hydrogen  gas.  The  production  of  carbonic  acid  gas  in  this 
instance  depends,  of  course,  upon  the  presence  of  oxygen, 
stowed  away  in  the  muscle  previous  to  the  experiment. 
The  protoplasm  of  the  tissues  is  everywhere  the  chief  seat 
of  the  processes  of  oxidation.  If  a  separate  muscle,  free  of 
blood,  be  inclosed  in  a  gas  chamber,  it  will  absorb  more 
oxygen,  and  give  off  more  carbonic  acid  gas  during  con- 
traction than  during  rest.  Examination  of  the  blood  of  the 
femoral  veins  in  the  frog,  after  galvanisation  of  the  posterior 
extremities,  shows  an  increase  in  the  amount  of  carbonic 
acid  gas. 

Oxidation  in  the  Blood. 

But  the  blood  is  also  a  vast  field  for  the  operations  of 
oxidation.    The  hamiato-globulin,  the  albumenoid  principle 


OXIDATION  IN  THE  BLOOD.  137 

of  the  blood  corpuscles,  collects  it  at  the  lungs,  and  carries 
it  in  loose  combinations  for  surrender  to  the  various  tissues 
of  the  body.  Then  the  blood  corpuscles  are  endowed  with 
what  we  might  term  a  magical  power  of  converting  oxygen 
into  ozone.  Ozone  (nascent  oxygen)  is  a  peculiar  modification 
of  oxygen,  with  much  higher  oxidising  powers  than  simple 
oxygen.  The  molecule  of  oxygen  being  represented  by  one 
O,  that  of  ozone  is  triplicated.  Ozone  is  03,  so  that  it  has 
much  wider  range  of  affinity.  If  a  drop  of  blood  be  let  fall 
upon  a  piece  of  ozone  test  paper  (made  test  paper  by 
having  been  saturated  in  tincture  of  guiacum,  and 
afterward  dried)  a  deep  blue  color  forms  about  it.  This 
is  the  reaction  of  ozone.  The  serum  of  the  blood  will 
not  show  it  at  all  (Schmidt).  The  ozone  of  the  blood 
can  not  be  directly  established  in  this  way,  as  it  is 
at  once  used  up  for  oxidation  purposes.  The  ozone 
thus  proven  present  has  been  just  created  by  the  blood 
corpuscles. 

The  blood,  again,  very  greatly  assists  the  oxidation  process 
by  its  alkalinity.  All  alkalies  have  this  property.  Many 
organic  compounds,  not  at  all  affected  by  oxygen,  are  at 
once  attacked  in  the  presence  of  a  free  alkali.  The  organic 
acids  ingested  into  the  body  pass  over  unchanged  into  the 
urine,  or,  at  most,  are  oxidised  to  very  slight  degree ;  but 
when  they  reach  the  blood  in  alkaline  combinations,  they 
are  at  once  completely  oxidised,  and  appear  as  carbonates 
in  the  urine.  Gallic  and  pyrogallic  acids,  are  not  oxidised 
in  the  atmosphere,  but  on  the  addition  of  a  free  alkali, 
oxidation  occurs  so  quickly  that  the  solution  of  pyrogallic 
acid  can  be  used  in  eudiometry,  and  sugar  becomes  so 
oxidisable  in  the  presence  of  a  free  alkali  that  it  will  abstract 
a  part  of  its  oxygen  from  a  metallic  oxide,  and  thus  reduce 
an  oxide  of  copper,  for  instance,  to  a  sub-oxide  (Trommer's 
test  for  sugar).     According  to  Gorup-Besanez,  even  ozone 

12 


138  OXIDATION  IN  NERVE  TISSUE. 

will  not  oxidise  the  organic  acids  except  in  the  presence  of 
a  free  alkali  or  alkaline  salts  ( Vierordt). 

Oxidation  in  Nerve  Tissue. 

Nerve-force  was  thought,  at  least,  to  be  generated  more 
directly  by  oxidation  of  nerve-substance,  as  the  quantity  of 
alkaline  phosphates  in  the  urine,  the  product  of  oxidation 
of  the  phosphorised  fats  of  nervous  tissue,  stands  in  close 
correspondence  to  the  amount  of  brain-work.  "We  may 
rightly  liken  the  brain,"  said  Carpenter,  "to  a  galvanic  battery, 
and  the  blood  to  its  exciting  liquid.  When  the  circuit  is 
closed,  a  rapid  oxygenation  of  the  nerve-substance,  as  of 
the  zinc  of  the  battery,  takes  place  ;  and  a  corresponding 
equivalent  of  nerve-force  (which  seems  closely  related  to, 
but  is  not  identical  with,  electricity)  is  generated."  Lut 
the  fact  alone  of  the  enormous  supply  of  blood  to  the  brain ; 
one-fifth  of  the  whole  amount ;  though  the  brain  weighs 
only  one-fortieth  of  the  entire  weigh t.of  the  body  ;  would  in- 
dicate that  nerve-force,  as  well  as  muscular,  is  almost  entirely 
derived  from  oxidation  of  material  furnished  by  the  food. 

Paul  Bert  has  been  able  to  prove  that  the  loss  of  con- 
sciousness and  motion,  which  occurs  immediately  when 
the  blood-current  to  the  brain  is  interrupted,  is  due  to  the 
lack  of  oxygen  rather  than  of  any  other  nutrient  matter. 
In  cases  of  partial  asphyxia,  induced  by  abstraction  or 
rarefaction  of  oxygen  (as  in  mountain  ascents)  the  faintness 
and  exhaustion  are  immediately  and  completely  relieved  by 
the  inspiration  of  oxygen  gas  or  of  air  which  is  highly 
charged  with  it.  The  transformations  of  force  that  occur 
in  the  body,  that  is,  the  manifestations  of  life,  are,  thus,  pre- 
eminently, processes  of  oxidation. 

The,.  Quantity  of  Oxygen  in  the  Body. 
In  recognizing  this  fact  we  would  be  led  to  believe  that 
the  quantity  of  this  gas,  and  its  most  frequent  product, 


QUANTITY   OF   OXYGEN   IN   TIIE   BODY.  139 

carbonic  acid,  in  the  blood  and  tissues  would  always  be 
very  great.  We  observe,  however,  the  very  reverse  to  be 
true.  There  can,  at  no  one  time,  be  collected  from  the 
blood  more  than  four  grammes  of  oxygen  or  carbonic  acid, 
and  adding  to  this  the  quantity  present  in  the  tissues 
(a  quantity  which  can  not  yet  be  definitely  ascertained, 
but  which  is  known  to  be  very  small),  the  whole  amount 
of  these  gases  is  still  comparatively  little.  But  this  small 
amount  present  at  any  one  time  is  no  true  criterion 
of  the  sum-total  absorbed  in  the  course  of  time.  For  this 
small  quantity  is  being  so  continuously  received  (and 
consumed)  as  to  amount  in  the  course  of  a  year  to  several 
hundred  pounds.  In  fact,  more  oxygen  is  ingested  than 
food  (aside  from  drink).  The  absolute  indispensability  of 
oxygen  gas  from  moment  to  moment,  is  proven  by  the 
serious  changes  that  at  once  ensue  in  the  body  when  its 
quantity  is  diminished  in  the  air.  Other  nutrient  matter 
may  be  absent  from  the  body  for  hours  or  for  days,  with- 
out discomfort,  but  the  absence  of  oxygen  for  a  few  seconds 
or  minutes  produces  serious  suffering.  It  is  the  long  subjec- 
tion of  individuals  with  inherited  vulnerable  constitutions 
to  an  atmosphere  whose  oxygen  has  been  reduced  (as  in 
factories,  badly  ventilated  houses,  etc.)  that  forms  the 
principal  factor  in  developing  phthisis,  pre-eminently  a  dis- 
ease of  modern  civilisation.  And  fresh  air  in  abundance  is 
the  only  specific  in  its  cure.  Fortunately,  oxygen 
exists  in  nature  in  sufficient  abundance,  for  all  the  wants 
of  protoplasm.  It  forms  eight-ninths  of  the  wTater  of  the 
globe,  nearly  one-half  of  the  solid  crust  of  the  earth,  and  one- 
fifth  of  its  air. 

Oxygen  is,  in  short,  an  essential  constituent  of  living 
protoplasm,  which  develops  only  at  the  bottom  of  an  ocean 
of  it,  thousands  of  cubic  miles  in  extent.  The  atmospheric 
ocean,  which  is  as  much  a  part  of  the  earth  as  its  water  or 


140  THE  GENESIS  OF  PROTOPLASM. 

its  salts,  is  an  inexhaustible,  a  perpetually-filling  reservoir 
of  oxygen  gas. 

We  have  now  to  consider  the  mode  of  origin  or  birth  of 
protoplasm,  and  its  mode  of  dissolution  or  death. 

The  Genesis  of  Protoplasm. 

When  the  microscope  first  began  to  disclose  its  revela- 
tions concerning  the  construction  of  living  things,  it  was 
hoped  that  we  were  at  last  in  possession  of  the  means 
that  would  lift  the  veil  of  mystery  concealing  the  genesis 
of  life.  If  was  believed  that  it  would  be  only  necessary 
to  perfect  the  instrument  for  the  highest  magnification  to 
enable  us  to  see  the  first  aggregation  of  atoms  to  constitute 
life.  It  is  needless  to  say  that  such  extravagant  concep- 
tions soon  proved  to  be  delusive.  With  the  microscope  on 
the  one  hand,  and  chemical  analysis  on  the  other,  the  physi- 
cal basis  of  life  was  soon  resolved  into  its  histological  and 
chemical  elements ;  but  no  peculiar  principle  of  life  was 
ever  thus  discovered.  It  seemed,  indeed,  a  j ustification  of 
the  exclamation  of  Schiller : — 

"Und  noch  Niemand  hat  erkundet 
Wie  die  grosse  Mutter  schafft 
Unergriindlich  ist  das  wirken 
Unerforschlich  ist  die  Kraft." 

(As  yet  no  one  has  discovered 
Nature's  secret  to  produce; 
Still  impenetrable  her  method 
Yet  inscrutable  her  force). 

The  microscopists  soon  found  themselves,  said  Leydig,  in 
the  predicament  of  individuals  who  had  long  studied  from 
afar  the  appearance  of  a  meadow  or  a  forest.  They  thought 
that  a  nearer  approach  would  inform  them  about  the 
germination,  the  growth  and  the  coloration  of  the  plants. 
Many  new  observations  they  did  make,  it  is  true,  but  the 


THE   GEXESIS   OF   PROTOPLASM.  141 

puzzling  riddles  remained  the  same.  They  stood  before  the 
same  questions,  with  the  difference  only  that  they  could 
now  study  the  changes  in  each  individual  plant,  which  they 
could  observe  before  upon  the  whole  green  surface. 

The  physiologist  thus,  aided  with  the  microscope  and 
the  test-tube,  took  only  a  closer  view  of  the  individual 
elements  aggregated  in  the  construction  of  living  things. 

In  the  impossibility,  then,  of  recognising  in  the  construc- 
tion of  animate  bodies  any  elements  or  principles  different 
from  the  inanimate,  the  question  at  last  arose:  Is  there 
really  any  such  difference?  Thus  the  question  stands  at 
the  present  time,  the  burden  of  proof  resting  upon  those 
who  still  maintain  the  existence  of  such  a  difference. 

The  question  of  spontaneous  generation  (autogeny)  is  now 
being  examined  and  discussed  with  even  more  interest  and 
with  more  probability  of  final  solution  than  ever  before 
in  the  history  of  science.  The  doctrine  of  evolution  ;  which 
may  now  be  regarded  as  an  accepted  fact,  and  which  must 
soon  become  incorporated  into  the  curriculum  of  our  com- 
mon schools;  followed  to  its  utmost  limits,  compels  the 
ultimate  admission  of  the  spontaneous  genesis  of  living 
matter.  But  an  inference,  however  legitimate  or  rational, 
does  not  constitute  a  fact  in  natural  or  any  other  branch  of 
science.  If  the  question  could  be  settled  by  the  mere  ex- 
pression of  opinion,  I  should  say,  with  becoming  diffidence, 
that  for  my  own  part,  I  side  completely  with  Prof.  Owen, 
the  highest  living  authority  in  comparative  anatomy,  and 
until  very  lately,  with  Quatrefages,  the  most  dangerous 
opponent  to  the  theory  of  evolution,  when  he  declares  him- 
self the  champion  of  spontaneous  generation  and  maintains, 
as  in  the  last  pages  of  the  third  volume  of  his  Anatomy  of 
the  Vertebrates,  that  the  formation  of  living  beings  out  of 
inanimate  matter  by  the  conversion  of  physical  and  chemi- 
cal into  vital  modes  of  force  is  a  matter  of  daily  and  hourly 


142  OMNE   VIVUM   EX   OVO. 

occurrence.  But  you  will  accept  as  conclusive  no  opinions. 
1  leave  you,  what  you  will  doubtless  exercise  anyhow,  the 
widest  latitude  of  belief,  until  proof  positive  shall  have 
been  advanced.  But  I  warn  you  that  there  is  here,  as  every 
where  in  science,  no  room  for  fancy,  feeling,  or  prejudice. 
Cold  as  ice,  clear  as  crystal,  science  is  a  synonim  of  truth. 
We  cannot  mould  the  truth  to  our  wants  and  fancies. 
There  is.  nothing  left  but  to  adapt  ourselves  to  truth,  what- 
ever wTreck  of  prejudice  its  revelations  may  imply.  Above 
all  things,  truth. 

Whatever  may  have  been  the  genesis  of  protoplasm 
under  the  very  different  conditions  of  the  primeval  world, 
or  whatever  it  may  be  now  under  conditions  somewhat 
similar,  at  the  bottom  of  the  sea,  for  instance,  are  questions 
still  unsettled.  So  far  as  we  have  positive  knowledge,  and 
it  is  of  facts  alone  that  we  have  any  right  to  speak,  every 
cell  arises  from  a  pre-existent  cell. 

Omne    Vlvum    ex   Ovo 

and  omnis  cellula  e  cellulis  are  other  well-known  axioms,  ex- 
pressive of  the  exclusive  derivation  of  new  protoplasm  from 
older  protoplasm  before  it.  Science  at  present  recognises 
no  other  birth  of  protoplasm  save  that  derived  from  parent- 
age. The  microscope,  in  discovering  the  eggs  of  plants  and 
animals  in  concealed  places,  has  put  to  flight  many  wild 
ideas  concerning  the  spontaneous  generation  of  animal  and 
Vegetable  life.  And  when  these  ova  or  germs  have  been 
so  minute  (in  the  case  of  bacteria,  etc.)  as  to  have  evaded 
the  highest  powers  of  the  microscope,  a  beam  of  electric 
light  (Tyndall)  has  disclosed  to  the  naked  eye  myriads  of 
combustible  (organic)  particles,  the  cultivation  of  which  in 
breeding  experiments  (Dallinger  &  Drysdale)  has  resulted 
in  visible  forms. 


REPRODUCTION   AND  NUTRITION.  143 

Reproduction  and    Nutrition. 

In  our  day  we  regard  the  reproduction  of  protoplasm 
entirely  as  a  phenomenon  of  nutrition.  It  is  part  of  the 
chemical  nature  of  protoplasm  that  an  isolated  mass  of  it, 
increased  by  assimilation  to  a  certain  size,  has  the  dispo- 
sition to  divide,  the  divisions  again  dividing,  and  so  on, 
in  the  formation  of  new  masses,  isolated  as  before.  Be- 
production  is  division  and  separation  in  growth  beyond 
the  natural  limit  of  size.  Nutrition  and  reproduction  are, 
as  we  have  seen,  the  fundamental  characteristics  of  pro- 
toplasm, and  they  stand  in  the  most  intimate  relation 
toward  each  other.  One  continues  the  individual,  the 
other  continues  the  species.  Nutrition  consists  of  a  con- 
stant change  of  matter  in  the  body  of  the  individual ;  re- 
production of  a  constant  change  of  individuals.  Nutri- 
tion, in  its  essence,  is  only  a  reproduction  of  atoms  of 
matter  in  the  body  of  the  individual,  which  atoms,  when 
increased  beyond  the  natural  limits  of  size,  separate  to 
reproduce  new  individuals.  Hence  it  becomes  a  physi- 
ological law  that  a  more  rapid  nutrition  implies  a  more 
rapid  reproduction.  The  better  fed  domesticated  animals 
breed  faster  than  their  ancestral  wild  forms.  More  human 
beings  are  born  in  times  of  plenty  than  in  times  of  famine. 
Of  course,  if  the  nutritive  matter  be  consumed  in  the  pro- 
duction of  other  forces,  as  in  the  growth  of  the  body, 
muscular  or  mental  work,  the  power  of  reproduction  is 
limited.  During  youth  and  adolescence  the  force  of  re- 
production is  absent  entirely,  or  is  very  limited.  Animals 
made  to  perform  mechanical  (muscular)  work  have  less 
progeny  (stallions,  etc.,  are  kept  idle  in  the  stalls);  and  human 
beings  of  high  mental  activity  are  comparatively  infecund. 
Nothing  so  completely  detracts  from  muscular  and  mental 
force  as  venereal  excess. 


144  THE  BIRTH  OE    THE  CELL. 


Modes    of  Cell   Genesis. 


> 


With  this  knowledge  of  the  physics  of  reproduction, 
we  are  not  surprised  to  learn  that  its  material  manifesta- 
tions are  simply  divisions  of  the  parent  cell.  This  division 
may  concern  the  protoplasm  first,  so  that  a  more  or 
less  central  constriction,  vertical  or  horizontal,  deepens 
to  a  furrow,  and  finally  completely  separates  the  main 
mass  and  its  nucleus  (when  it  exists)  into  two,  each  of 
which  then  commences  its  independent  existence.  In 
more  complex  structures  the  division  of  the  generative 
cell  (ovum)  proceeds,  each  division  subdividing,  until 
finally  the  original  cell  presents  the  appearance  of  a  mul- 
berry. This  process  of  segmentation,  as  it  is  called,  pro- 
vides separate  atoms  in  each  part  of  the  subdivided  cell 
for  the  construction  of  separate  organs  and  tissues.  The 
wall  of  the  original  "mother"  cell  may  remain  intact 
while  this  "endogenous"  production  of  new  cells  is  tak- 
ing place  within  it,  and  may  even  take  part  in  the  construc- 
tion of  the  new  product,  or  it  may  burst,  as  it  were,  and 
permit  the  new  "daughter"  cells  to  escape  and  provide 
for  themselves.  The  ovum  or  primordial  cell  is  a  typical 
example  of  the  first  method  of  procedure,  cartilage  cells 
of  the  second.  In  the  cartilage  cell,  as  in  the  white  blood 
corpuscles  of  mammals,  birds  and  amphibious  animals, 
and  in  the  red  blood  corpuscles  of  the  embryos  of  mam- 
mals and  birds,  the  division  first  affects  the  nucleus, 
which  splits  in  two,  each  half  aggregating  about  itself,  by 
molecular  motion,  a  quantity  of  protoplasm  until  the  en- 
tire mass  is  thus  divided.  Such  corpuscles  are  sometimes 
encountered  with  1-2-4  nuclei,  each  of  which  attracts  suffi- 
cient protoplasm  to  subsequently  form  a  separate  cell. 
So-called  "giant  cells,"  which  play  such  an  important  role 
in  rapidly  proliferating    structures    (cancer,   tuberculosis, 


THE   DEATH   OF   CELLS.  145 

etc.),  are  produced  by  a  rapid  multiplication  of  nuclei 
■without  corresponding  division  of  the  surrounding  proto- 
plasm. 

Or,  finally,  the  division  of  the  cell  (protoplasm)  may  be 
more  lateral  than  uniform,  protrusions  shooting  out  from 
the  mass  of  protoplasm  to  finally  separate  from  the  parent 
cell.  This  method  of  division  by  budding,  as  it  is  called, 
is  mostly  characteristic  of  the  vegetable  cell,  but  occurs 
also  in  animal  cells  (polyps,  tape-worms,  etc.),  and,  as  a 
rule,  in  the  regeneration  of  all  cells  after  partial  destruc- 
tion of  tissue.  The  yeast  plants  (torulae)  which  rapidly 
develop  in  myriads  in  solutions  of  sugar,  and  are  the  imme- 
diate cause  of  all  fermentation,  are  convenient  objects  for 
the  study  of  reproduction  by  gemmation. 

The  Death   of  Cells. 

The  cell  (protoplasm)  having  thus  been  born,  it  serves 
its  special  purpose  in  the  animal  economy,  and  dies.  The 
final  dissolution  and  disappearance  of  the  individual  cell 
may  occur  in  several  ways.  In  the  first  place,  it  may 
simply  lose  its  fluid  contents,  dry  up  and  desquamate,  that 
is,  be  mechanically  rubbed  away.  Such  a  mode  of  death 
characterises  cells  exposed  to  the  open  air,  as  the  epithel- 
ium cells  of  the  skin.  Or,  cells  may  perish  from  excess  of 
fluid,  be  washed  away  and  lost.  This  mode  of  death  oc- 
curs in  superficial  mucus  cells.  The  "rice-water"  appear- 
ance of  cholera  discharges  is  due  to  the  presence  of  mul- 
titudes of  intestinal  mucus  cells,  washed  off  by  excessive 
drainage  into  the  intestinal  tube.  Cells  again  may  be  killed 
by  such  rapid  increase  (proliferation)  in  number  as  to  effect 
mutual  compression  and  expression  of  their  fluidity,  as  in 
the  caseous  degenerations  of  scrofula  and  phthisis. 

But  most  cells  die  by  liquefaction  of  their  contents ; 
conversion  of  their  protoplasm  into  fat,  or  mucus,  or  water. 

13 


146  CLASSIFICATIONS  OF    THE    TISSUES. 

These  substances  are  then  absorbed  from  the  shriveled 
cell  wall,  which,  in  turn,  finally  disappears.  Lastly,  the 
protoplasm  of  the  cell  may  be  substituted  by  the  salts  of 
lime,  and,  undergoing  this  calcareous  degeneration,  cease 
to  functionate  as  cells.  The  vast  majority  of  cells  die  a 
natural  death  by  fatty  or  calcareous  degeneration. 

Recapitulation. 

The  body  of  an  animal  or  plant  consists,  as  we  have 
seen,  of  a  single  cell,  or  of  an  aggregation  of  such  cells. 
The  single-celled  bodies  are  said  to  be  simple,  the  many- 
celled,  compound  bodies.  These  structures  are,  however, 
in  essence  the  same  :  the  simple  bodies  being  simply  sep- 
arated further  from  each  other.  One  such  body  (cell) 
depends  for  its  existence  (sustenance)  upon  other  bodies. 
In  the  compound  body,  the  single  cells  are  also  in  a  sense 
individual,  yet  they  are  all  mutually  dependent.  A  com- 
pound body  is  like  a  colony  of  ants  or  a  hive  of  bees ; 
completely  isolated  individuals  perish.  The  cells  in  a 
compound  body  are  connected  together  by  fluid,  or  more 
or  less  solid,  intercellular  substance.  The  intercellular 
substance  is  the  product  of  cells.  A  compound  body  is 
made  up  of  cells  and  intercellular  substance. 

Classifications  of  the  Tissues. 

Like  cells,  differentiated  from  the  rest,  and  grouped  to- 
gether for  a  special  purpose,  constitute  the  organs  or 
tissues  of  a  compound  body.  The  body  thus  comes  to  be 
made  up  of  organs  and  tissues,  each  having  a  special  and 
particular  purpose  to  subserve  for  the  benefit  of  other 
organs  and  tissues  as  well  as  of  itself.  The  body  is,  hence, 
constructed  upon  a  plan  of  a  division  of  labor;  just  as 
society  is  composed  of  farmers,  tradesmen,  thinkers,  etc. 


ANATOMICAL    AND   CHEMICAL  CLASSIFICATION.       147 

Anatomical   Classification. 

If  we  regard  the  tissues  of  the  body  simply  from  an 
anatomical  stand-point,  we  recognize: — 

1.  Tissues  composed  of  simple  cells,  with  fluid  inter- 
cellular substance,  as  the  blood,  the  lymph  and  chyle. 

2.  Tissues  composed  of  simple  cells,  with  a  small 
amount  of  solid  intercellular  substance,  as  the  epithelium, 
nail,  etc. 

3.  Tissues  composed  of  simple  or  transformed  cells 
cohering  (in  some  cases),  situated  sometimes  in  homo- 
geneous, sometimes  in  fibrous,  and,  as  a  rule,  more  or  less 
solid  intermediate  substance,  as  cartilage,  colloid  tissue, 
adipose  tissue,  fibrous  and  elastic  tissue,  dentine  and  bone 
(connective  tissue  group). 

4.  Tissues  composed  of  transformed,  and,  as  a  rule, 
non-cohering  cells,  with  scanty,  homogeneous  and  more 
or  less  solid,  intermediate  substance,  as  enamel,  lens  and 
muscle. 

5.  Tissues  so  mixed  as  to  admit  of  no  grouping  under 
any  of  the  above  heads;  as  nerve  tissue,  gland  tissue, 
vessels  and  hairs. 

This  is  the  histological  classification  of  Frey. 

Chemical    Classification. 

If  we  regard  the  body  from  a  purely  chemical  stand- 
point, we  shall  have  to  recognize  its  separation  into  the 
three  great  classes  of  proximate  principles: — 

1.  The  inorganic  principles ;  definite  in  their  chemical 
composition,  crystallizable,  derived  exclusively  from  with- 
out (forming  to  great  extent  the  crust  of  the  earth),  sub- 
serving their  special  purpose  in  the  body  and  then  being 
voided  from  it,  having  undergone  little  or  no  change;  as 
water,  common  salt,  phosphate  of  lime,  etc. 


118  PHYSIOLOGICAL  CLASSIFICATION. 

2.  The  non-nitrogenized  or  hydro-carbonaceous  prin- 
ciples ;  which,  as  their  name  implies,  contain  no  nitrogen, 
but  are  made  up  of  carbon  in  large  quantity,  and  of  hydro- 
gen and  oxygen  ;  principles  which  do  not  belong  to  the 
crust  of  the  earth,  but  are  formed  exclusively  in  the 
bodies  of  animals  and  plants,  where  they  undergo  such 
changes  as  to  be  entirely  broken  up  and  consumed  as  such ; 
as  starch,  the  sugars  and  the  fats. 

3.  The  nitrogenized,  albumenoid  or  protein  bodies;  in- 
definite in  their  chemical  composition,  containing  nitro- 
gen and  mineral  matters  in  addition  to  the  carbon,  hydro- 
gen and  oxygen,  varying  in  consistency  according  to  the 
consistence  of  the  organ  in  which  they  are  found,  hygro- 
scopic (that  is,  having  the  power  to  absorb  water  and  be 
restored  to  their  original  consistence  after  desiccation), 
coagulable,  spontaneously  or  artificially,  and  undergoing 
fermentation  and  putrefaction,  by  serving  as  food  to 
microscopic  animals  and  plants,  which  split  up  their  chemi- 
cal combinations  into  new  compounds  (alcohol,  carbonic 
acid  gas,  Water  and  other  products  of  decomposition), 
principles  also  formed  exclusively  in  the  vegetable  or  ani- 
mal cell  and  undergoing  entire  change  in  the  body. 
Examples  of  this  class  of  proximate  principles,  which 
includes  also  the  coloring  matters  and  certain  crystallized 
products  of  excretion,  are  albumen,  fibrin,  casein,  myosin, 
pepsin,  lecithin,  hcemoglobulin,  urea,  etc. 

This  is  the  chemical  classification  of  Eobin  and  Verdeil. 

Physiological    Classification. 

If,  however,  we  regard  the  construction  of  the  body 
from  a  purely  physiological  stand-point,  we  shall  have  to 
separate  the  tissues  into  classes  according  to  pre-eminence 
in  especial  properties,  with  all  the  rest  of  which  each  one 
is  endowed  in  subordinate  degree,  as  : — 


PHYSIOLOGICAL   CLASSIFICATION.  149 

1.  The  tissues  eminently  mechanical ;  bone  (including 
teeth ),  outside  layers  of  epithelium  (including  hair  and  nai Is). 

2.  The  tissues  eminently  contractile;  the  muscles. 

3.  The  tissues  eminently  irritable  ;  the  nerves  (and  nerve- 
centers). 

4.  The  tissues  eminently  secretory  (including  excretory)  ; 
the   digestive,  genito-urinary,  pulmonary,  etc.,  epithelium. 

5.  The  tissues  eminently  metabolic  (elaborative  or  trans- 
formative) ;  the  gland  cells. 

6.  The  tissues  eminently  reproductive  ;  the  ovary  and 
the  testis. 

This  is  essentially  the  classification  of  Michael  Foster. 

A  study  of  these  three  methods  of  classification  gives 
a  clear  survey  of  the  construction  and  action  of  the 
various  tissues  in  the  body,  whether  simple  or  complex. 
These  properties  and  actions  in  the  simplest  forms  of 
protoplasm,  like  the  amoeba,  are  very  few  and  very  limited. 
Under  favoring  conditions  and  in  many  millions  of  years, 
aggregated  masses  of  protoplasm  build  up  the  most 
complicated  structures.  At  various  periods  in  the  history 
of  our  earth. 

"In   days  of  yore,   no  matter  where  or  when 
Before  the  low   creation   swarmed  with  men." 

different  animals  have  successively  held  the  dominant 
place.  At  the  present  time  the  highest  and  most  complicated 
structure  is  the  body  of  man.  But  the  principles  of  con- 
struction, the  general  properties  of  composition,  remain 
everywhere  the  same.  What  is  true  of  the  monad,  is  true 
of  man.  The  binary  compounds  of  inorganic  matter, 
carbonic  acid  gas  (COO),  and  water  (HHO),  are  raised  in 
organic  matter  to  ternary  compounds,  starch,  etc.  (CHO),  and 
upon  the  question  whether  this  rearrangement  of  elements 
happens  naturally,  i.  e.,  chemically,  or  supernatural ly,  rests 
the  most  momentous  problem  of  our  day. 


150  BONE  AND  ITS  PROPERTIES. 


LECTURE    VIII. 


BONE  AND  ITS  PROPERTIES. 

CONTENTS. 

Anatomical  Dignity  of  Bone — Relation  of  Bone  to  Nerve  Tissue— 
The  Skeleton— The  General  Properties  of  Bones — The  Histology  of 
Bone— The  Haversian  Canals — The  Lamella? — The  Bone  Corpuscles 
and  Lacuna? — The  Canaliculi — The  Chemistry  of  Bone — Difficulties 
Attending  the  Study  of  Osteology — Bones  as  Fuel — Gelatine  as  an 
Aliment — The  Resistance  and  Resilience  of  Bone — Constancy  of 
Chemical  Composition — Rachitis  andOstco-Malacia — The  Phosphate 
of  Lime — The  Preservation  of  Bone — Bone  a  Connective  Tissue — 
The  Formation  of  Bone — The  Periosteum — The  Centre  of  Ossification 
— Tho  Determination  of  Age — The  Femoral  Epiphyseal  Centre — The 
Excavation  of  Bone — Air  in  Bone — The  Marrow — Studies  in  Living 
Bone — Eonc  as  a  Symbol  of  the  Body. 

The  Anatomical  Dignity  of  Bone. 

Bone  has  a  structural  dignity  which  is  attained,  with  one 
exception,  by  no  other  hard  or  solid  formation  in  the 
economy  of  nature.  The  existence  of  true  bone  in  the 
body  of  an  animal  brings  it  to  rank  at  once  among 
the  class  of  vertebrates.  Wherever  is  bone,  is  a  spinal 
column.  The  hard  parts  of  all  invertebrate  animals  are 
made  of  horn  and  shell,  never  of  true  bone.  Even  the 
teeth,  which  alone  among  other  solid  structures  enjoy  the 
same  exceptional  place,  from  the  stand-point  of  compara- 
tive anatomy,  could  not  be  present  at  all,  were  it  not  for  the 
fact  that  their  roots  are  incrusted  with  a  layer  of  bone,  the 
cement,  whose  periosteum  fusing  with  that  of  the  alveolae 
of  the  bones  of  the  jaws,  secures  their  fixation  in  the  body. 

Relation  of  Bone  to  Nerve  Tissue. 

For  the  bone  in  the  spinal  column  of  the  vertebrata 
stands  in   the   most  intimate  .  relation   to  the  great  chain 


*  c 

Fig.  21. — The  structure  of  bone,  a,  b,  the 
Haversian  canals,  c,  d,  the  Haversian  lamellae. 
e,  e,  periosteal  lamellae.  f,g,  the  bone  cells  and 
canaliculi.     (p.  153-156) 


-h 


Fig.  22. — The  structure  of 
striped  muscle,  a  (left  fig- 
ure), sarcolemma.  b,  end  of 
ruptured  fibre,  a  (right  fig- 
ure), transverse  striae.  £,  h- 
brilla.    (p.  178-179) 


Fig.  23. — Involuntary 
(smooth)  muscle  fibre,  a, 
nucleus,     (p.  182) 


Fig.  24. — Termination  of  motor  nerve  in 
voluntary  muscle.  The  muscle  fibres  exhibit 
the  striae  and  sarcolemmar  nuclei;  the  nerve, 
its  constituent  parts  and  the  terminal  plates. 
(P-  231) 


Fig.  25. — Schematic  representation  of  re- 
flex  action.       1,  sensitive   (epithelial)  sur- 
face.    2,    motor    (muscular)    structure.     A, 
afferent  (sensitive)    nerve;  B,  nerve  cell;     - 
C,  efferent  (motor)  nerve,     (p.  237)  L 


Fig.  26. — Schematic  representation  of 
volitional    action.     1,  sensitive  surface.     2,   motor  structure.       A,   afferent  nerve; 
C.  efferent  nerve;  B,  nerve  cell  (for  simple  reriex  action).  Z>,  afferent  nerve;    F 
efferent  nerve;   £.,  nerve  cell  (for  volitional  action),     (p.  238) 

The  Structure  of  Bone  and  Muscle,  and  the  Modus  Operandi  of  Reflex  Action. 


THE  SKELETON.  151 

of  nervous  matter,  the  spinal  cord,  which  it  encloses  and 
protects.  Each  vertebra  corresponds  to,  and  is  developed 
in  connection  with,  one  of  the  primitive  ganglia  of  the 
nervous  system.  Above  it  and  below  it  emerge  the  spinal 
nerves.  So  that  a  vertebra  has  been  defined  to  be  "a  bone 
or  axial  segment  of  the  skeleton  included  between  two 
pairs  of  nerves."  The  subsequent  growth  of  the  column, 
however,  faster  than  the  cord,  disturbs  this  topical 
relation  so  that  the  cord  which  at  the  third  month 
of  intra-uterine  life  reaches  as  low  as  the  end  of  the 
sacrum,  if  not  to  the  coccyx,  stops  short  in  the  adult  at  the 
second  lumbar  vertebra.  The  spinal  nerves  then  come  to 
pass  down  from  the  cord  and  out  through  the  interverte- 
bral foramina  with  such  a  degree  of  obliquity,  increasing 
from  the  first  to  the  last  pair,  that  it  would  seem  as  though 
the  cord  had  been  drawn  upwards,  bodily,  within  the  spinal 
canal. 

The  Skeleton. 

The  bones  of  various  shape  and  size,  jointed  together 
in  various  ways,  constitute  the  skeleton  or  scaffolding,  whose 
disposition  determines  the  size,  shape,  posture,  in  short, 
the  configuration  and  habitus  of  the  animal: — Ossa  autem 
corpori  humani  for  mam,  rectitudinem  et  firmitatem  conciliant 
(Galen). 

The  word  skeleton  is  often  said  to  be  derived  from 
ax&hu,  to  dry  up,  in  the  sense  in  which  this  term  was  used 
by  Herodotus  who  speaks  of  the  sole  aridum  et  exsiccat- 
um  cadaver,  which  the  Egyptians  exhibited  at  their  festivities, 
with  the  greeting,  edite  et  bibite,  post-mortem  tales  eritis! 
Skeleton  is  more  probably  derived  from  gx^oq,  thigh 
bone,  which,  as  the  largest  bone  in  the  body,  had  its  name 
used  as  a  designation  for  the  whole  structure  (Hyrtl). 

In  the  Crustacea,  molluscs  and  in  insects,  the  skeleton^ 


152  GENERAL  PROPERTIES  OF   BOXES. 

of  shell  or  horn,  is  on  the  exterior  of  the  body.  The  first 
example  of  internal  skeleton  is  met  in  the  cephalopodous 
molluscs  in  which  certain  cartilaginous  plates  are  inclosed 
in  the  body  of  the  animal  protecting  certain  parts  of  the 
nervous  system. 

General  Properties  of  Bones. 

The  elongated,  tubular,  bones  of  the  extremities  serve  as 
levers  for  the  muscles,  to  the  action  of  which,  by  their 
restriction,  of  movement,  they  lend  precision  and  effect. 
Hence  the  bones  are  often  mentioned  as  the  passive  organs 
of  locomotion.  Spread  out  in  surfaces,  more  or  less  flat,  or 
stretched  out  in  rods,  more  or  less  flexible,  they  form  cavities, 
the  skull ;  or  basins,  the  pelvis ;  or  cages,  the  thorax,  for 
the  protection  and  support  of  the  softer  organs.  Broken  up, 
as  it  were,  into  smaller  fragments,  with  irregular  surfaces 
and  spongier  structure,  often  with  intercalated  cartilaginous 
pads,  they  act  as  bumpers  or  cushions  to  break  the  force  of 
shocks,  as  at  the  wrist  and  ankle  and  in  the  spinal  column. 
Contracted  in  their  shafts,  or  alternately  convex  and 
concave  in  their  course,  as  in  the  long  bones  and  vertebral 
column,  they  give  space  for  the  origin  and  lodgment  of 
muscles,  and  support  to  the  heavier  organs,  and  expanded 
at  their  ends,  they  widen  the  surface  of  articulation,  afford 
room  for  the  insertion  of  ligaments  and  tendons,  and  furnish 
fulcra  for  the  action  of  the  muscles,  by  distancing  the 
point  of  insertion  from  the  centre  of  motion.  Increased  in 
weight  and  size  near  the  trunk,  they  give  momentum  and 
range  to  the  movements  of  the  body,  and  abbreviated  in  all 
their  dimensions  at  their  distal  extremities,  they  lend  celerity 
and  accuracy  to  its  various  actions.  They  are  thickened 
into  massive  bars  and  plates  as  in  the  pubes  and  ilium, 
thinned  down  to  papyraceous  sheets,  or  rolled  up  in  delicate 
scrolls  as  in  the  nasal  fossa?,  projected  in  vast  promontories 


THE   HAVERSIAN   CANALS.  1q3 

in  the  various  tuberosities,  or  reduced  to  insignificant  frag- 
ments as  in  the  bones  of  the  ear,  all  for  purposes  familiar 
to  every  student  of  anatomy. 

The  Histology   of   Bone. 

The  microscopic  appearance  of  bone  is  characteristic. 
For  bone  belongs,  histologically,  to  the  group  of  the  con- 
nective tissues  and  hence  consists,  primarily,  of  a  network 
of  stellate  ramifying  cells  (bone  cells,  bone  corpuscles,  cor- 
puscles of  Purkinje,  etc.).  In  the  subsequent  process  of 
ossification  these  cells  desiccate  and  leave  spaces,  lacuna?, 
filled  with  serum  or  air  (carbonic  acid  gas).  The  hardness 
of  bone  is  due  to  the  deposit  of  various  mineral  salts,  prin- 
cipally of  lime,  in  the  intercellular  spaces.  Any  doubt  as  to 
the  nature  of  a  substance  is  at  once  resolved  under  the 
microscope,  so  far  as  bone  is  concerned,  at  a  single  glance. 

The  distinguishing  characteristics  of  bone  are  four,  viz., 
First, 

The  Haversian    Canals. 

These  canals  are  the  conduit  tubes  for  the  bloodvessels, 
the  main  trunks  of  which  penetrate  the  surface  of  the 
bones  at  the  so-called  nutritious  foramina.  Reaching  the 
interior  of  the  bone,  the  canals  ramify  throughout 
its  substance,  varying  in  size  from  -^  So0-  °f  an  incn 
(0.112S-0.0149  mm.)  in  diameter,  so  completely  sup- 
plying all  parts  of  it,  that  no  osseous  tissue  is  removed 
from  its  nutrient  blood  at  a  greater  distance  than 
the  yi^j  of  an  inch.  The  abundance  of  the  blood  supply  to 
bone  imparts  to  it  a  pinkish  hue,  though  the  fundamental 
color  of  bloodless  bone  is  a  pale  gray,  except  in  some  fishes 
where  it  is  green.  Bone,  like  all  other  vascular  structures, 
is  liable  to  inflammations,  and  wounded  bone  bleeds.  In 
cross  sections  of  bone,  the  bloodvessel  canals,  called  also  the 


154  THE  LAMEL.L2E. 

Haversian  canals,  to  perpetuate,  the  name  of  their  dis- 
coverer, Clopton  Havers  (1691),  appear  as  rounded  or  ovoid 
openings  of  various  size,  in  long  sections  as  split  canals. 

Where  the  bone  tissue  is  so  thin  that  it  may  be  directly 
nourished  by  the  vessels  in  the  two  enclosing  layers  of 
periosteum,  as  in  the  laminae  papyraceae  of  the  ethmoid  bone 
and  in  the  translucent  regions  of  the  palate  and  lachrymal 
bones,  and  in  the  leaves  of  spongy  tissue  every  where, 
Haversian  canals  are  not  developed.  In  the  flat  bones  of 
the  cranium,  etc.,  and  in  the  sternum,  the  Haversian  canals 
radiate  in  stellate  form  from  definite  points  (from  the  tuber 
frontale,  parietale,  etc.). 

Second, 

The   Lamella?. 

Bone  tissue  is  deposited  in  layers,  6-15  in  number,  each 
about  -^oVo  of  an  inch  (0.0065  mm.)  in  diameter,  about  the 
bloodvessels,  the  oldest  layers  being,  like  geological  strata,  the 
deepest,  that  is,  nearest  to  the  vessels.  Or,  the  layers  are 
formed  from  the  under  surface  of  the  periosteum  and  thus 
encircle  the  entire  bone.  As  the  bone  continues  to  grow,  the 
relation  of  these  layers  to  each  other,  of  course,  undergoes 
change.  That  is,  they  appear  to  abut  against  each  other 
like  the  upheaved  volcanic  strata  of  the  earth  against  the 
horizontal  aqueous  strata.  The  Haversian  lamellae  lie  con- 
centrically about  the  bloodvessel  canals,  and  as  these 
canals  in  the  long  bones  run,  for  the  most  part,  parallel 
with  the  long  axis  of  the  bone,  the  Haversian  lamellae  form 
series  of  columns  about  each  other  throughout  the  length  of 
the  bone,  connected  with  each  other,  braced,  as  it  were,  by 
the  lateral  columns  about  the  lateral  anastomosing  canals. 

A  singular  system  of  lamellae  first  described  by  Sharpey 
(1856),  as  perforating  bone  fibres,  pass  from  the  under  sur- 
face of   the  periosteum  downwards  through  the  circular 


THE   BONE   CORPUSCLE^.  155 

periosteal  layers  "like  nails  through  the  leaves  of  a  book, 
pinning  them  together."  They  arc  found  in  human  bone  as 
well  as  in  that  of  other  mammals,  but  more  frequently  in 
amphibia  and  fishes.  They  are  the  residue  of  the  connec- 
tive tissue  substance,  the  original  matrix  of  bone,  and  hence 
are  not  found  among  the  Haversian  canals. 

Third, 

The    Bone    Corjjuscles, 

corpuscles  of  Purkinje  (1834),  or  rather  the  lacunae,  the 
spaces  left  after  disappearance  of  the  corpuscles. 

These  lacunae,  ovoid,  and  with  their  radiating  canaliculi, 
stellate  in  shape,  are  seen  profusely  scattered  about  in  the 
microscopic  field  (Harting  counted  910  in  a  square  milli- 
meter of  bone),  lying  between  or  in  the  various 
lamellae.  They  measure  from  tiVo^soo  of  an  inch 
in  their  long  diameter  by  about  ^J^y  of  an  inch  in  width. 
(0.0181—0.0514X0.0068  mm.).  The  lacunae  (?mko^  lake), 
as  already  intimated,  are  the  open  spaces  filled  with  serum, 
in  dried  bone  with  air,  representing  the  sites  of  the  original 
bone  (connective  tissue)  cells.  In  the  process  of  ossifica- 
tion, mineral  matter  comes  to  be  deposited  about  the  bone 
cells,  which  finally  disappear,  leaving  the  lacunae  as  moulds 
indicating  their  former  site  and  size.  The  original  bone 
corpuscles  (protoplasm)  or  cells,  with  their  elongated 
nuclei,  may  only  be  obtained  from  fresh  (growing)  bone 
whose  mineral  matter  has  been  dissolved  out  by  hydro- 
chloric acid. 

Fourth, 

The    Canaliculi. 

These  are  the  minute  wavy  canals  which  make  communi- 
cation between  different  lacunae,  between  lacunae  and  Haver- 
sian canals,  and  between  lacunae  and  the  general  medullary 
cavity  (the  marrow).  They  merit  the  diminution  appended 
to  their  name,  as  they  measure  but  from  so£>-<roo  of  ari  incn 


156  THE  COMPOSITION   OF   BONE. 

in  length  and  ^  of  an  inch  (0.0514X0.0008  mm.)  in  width. 
Whether  the  contractile  bone  protoplasm  protrudes  filiform 
processes  into  these  tubes,  or  whether  they  permit  to 
circulate  in  their  interior,  nutritive  juices  to  ultra-vascular 
parts,  are  questions  still  unsettled.  That  they  may  serve  as 
communicating  tubes  is  proven  by  the  appearance  of  mer- 
cury in  numberless  points  upon  the  surface  of  bone  after 
its  insertion  into  the  medullary  cavity.  Gerlach  succeeded 
in  injecting  bone  with  various  coloring  and  hardening  sub- 
stances in  the  same  way. 

These  are  the  four  distinguishing  characteristics  of  bone. 
Any  tissue  which  does  not  exhibit  them  under  the  micro- 
scope, however  analogous  in  all  its  properties,  as  the  ivory 
or  the  dentine  of  the  teeth,  is  said  not  to  rise  to  the  anatom- 
ical dignity  of  true  bone. 

The    Chemistry   of  Bone. 

Bone  has  been  repeatedly  analysed  by  the  most  expert 
chemists,  and  though  the  results  obtained  have  differed  in 
unimportant  details,  on  account  of  the  difficulty  of  freeing 
its  tissue  from  substances  (fat,  blood,  etc.),  with  which  it  is 
intimately  commingled,  the  general  conclusions  remain 
about  the  same.  Thus  bone  is  found  to  be  composed  of 
two-thirds  mineral  and  one-third  animal  matter,  a3  the 
following  table,  deduced  by  Lehman  from  the  befat  umxl  v&es, 
exhibits : 

Composition  of  Bone. 

Phosphate  of  Calcium, r      57 

Carbonate  of  Calcium, -8 

Fluoride  of  Calcium, «•        1 

Phosphate  of  Magnesium, 1 

Mineral  matter,     -.---.      G7 
Animal  matter, 33 

ioa 


THE   STUDY   OF   OSTEOLOGY.  157 

The  mineral  may  be  readily  separated  from  the  animal 
matter  by  maceration  of  the  bone  in  dilute  hydrochloric 
acid.  '  The  size  and  shape  of  the  bone  remains  perfectly 
preserved  by  the  animal  matter  left,  which,  however,  is  so 
soft  and  pliable  that  long,  slender,  bones,  like  the  clavicle 
or  fibula,  may  be  tied  in  knots,  or  flat  bones,  like  the  scapula, 
crumpled  in  the  hand. 

The  animal  matter  may  be  likewise  destroyed  while  the 
mineral  matter  remains.  When  a  bone  is  subjected  to 
sufficient  heat  in  an  oven  to  drive  off  (decompose)  animal 
matter,  the  bone  first  turns  black  from  the  carbon  deposited 
on  its  surface.  The  carbon  is  subsequently  volatilised 
(oxidised),  however,  escaping  as  carbonic  acid  gas,  leaving 
only  the  white  bone  ash.  Though  the  size  and  shape  of  the 
bone  are  still  preserved  in  every  particular,  the  cohesion  of 
its  particles  is  nearly  destroyed,  the  whole  structure  crumb- 
ling away  on  the  slightest  touch.  The  bones  in  the  ancient 
catacombs  are  thus  wholly,  or  in  part,  reduced  by  the 
gnawing  tooth  of  time. 

Difficulties   Attending    the    Study  of  Osteology. 

If  bones  be  exposed  to  the  air  and  sun  during  this  pro- 
cess of  reduction,  they  gradually  dry  up  and  bleach  to  the 
color  and  consistence  of  their  mineral  constituents.  It  was 
only  from  such  specimens,  rejected  by  the  Tiber,  or  found 
upon  the  battle-fields  of  slaughtered  Germans,  that  the 
ancient  Romans  could  prosecute  their  studies  in  osteology. 
What  bones  escaped  cremation  with  them  had  to  be 
religiously  consigned  to  putrefaction  in  the  earth.  Galen 
was  compelled  to  travel  from  Pergamos  to  Alexandria  to  see 
a  perfect  skeleton.  It  is  highly  probable  that  he  never 
opened  a  human  body,  as  his  descriptions  of  organs  are 
only  those  of  the  ape  and  dog.  "The  age  in  which  he  lived, 
says  the  historian,  offered,  yearly,  thousands  of  human  lives 


158  GELATINE   AS   AX   ALIMENT. 

to  the  caprice  of  the  Roman  people,  and  their  cruel  Emperor 
even  cast  them  as  prey  to  the  wild  beasts  of  the  Coliseum, 
but  would  not  grant  one  single  dead  body  to  the  study  of 
science"  (Hyrtl). 

Bones  as  Fuel. 

So  long  as  the  animal  matter  of  bone  remains,  however, 
it  is,  of  course,  combustible,  and  is  even  used  as  fuel  in 
places  where  ordinary  fuel  is  scarce.  Thus  in  the  Falkland 
islands,  where  trees  are  few,  the  inhabitants  roast  the  flesh 
of  cattle  upon  fires  made  from  the  bones  mixed  with  turf, 
and  Darwin,  in  his  Voyage  Round  the  World,  relates  that 
the  Guachos  in  South  America,  where  there  was  very  little 
brushwood  for  fuel,  soon  made,  to  his  great  surprise,  a  fire 
nearly  as  hot  as  coals,  from  the  skeleton  of  a  bullock  lately 
killed,  whose  flesh  had  been  picked  away  by  the  carrion 
hawks.  They  told  him  that  in  winter  they  often  killed  an . 
animal,  cleaned  the  flesh  from  the  bones  with  their  knives  and 
then  with  these  same  bones  roasted  the  meat  for  their  suppers. 

Gelatine  as  an  Aliment. 

When  bone  is  boiled  with  water,  its  animal  matter  is  con- 
verted into  gelatine,  proof  that  bone  cartilage  is  not  common 
cartilage,  which,  when  boiled,  yields  chondrin,  a  very 
different  substance.  Though  the  gastric  juice  will  attack 
and  dissolve  gelatine,  it  has  very  little,  if  any,  nutritive 
properties,  and  should  never,  in  any  of  its  forms  (jellies, 
isinglass,  Iceland  moss),  be  relied  upon  as  an  article  of  diet. 
It  has  the  semblance  only,  not  the  substance,  of  food.  The 
gelatine  and  the  marrow  having  been  extracted  from  in- 
gested bone,  the  mineral  matter  escapes  with  the  feces. 
Such  hard,  white,  feculent,  matter  from  the  dog  was  admin- 
istered as  a  remedy  to  epileptics  in  old  times,  under  the 


RESISTANCE   AND   RESILIENCE   OF   BONE.  159 

classical  name  of  "Album  Grecum."  It  is  a  subject  for  con- 
gratulation that  the  therapy  of  this  disease  has  been  somc- 
what  improved  since  then. 

The  Resistance  and  Resilience  of   Bone, 

The  proportions  in  which  the  animal  and  earthy  matter 
are  united  in  bone  endow  it  with  its  peculiar  combination 
of  properties,  resistance  and  resilience.  Bone  has  twice  the 
resisting  force  of  solid  oak  and  nearly  three  times  as  much 
as  ash  or  elm.  The  elasticity  or  resilience  of  bone,  aided  by 
the  cartilaginous  structures  to  which  it  is  attached,  enables 
it  to  greatly  economise  muscular  force.  For  example,  the 
return  of  the  thorax  after  inspiration,  that  is,  the  whole  force 
of  tranquil  expiration  is  effected  by  the  elasticity  of  the  ribs 
and  cartilage,  and  the  deflected  spinal  column  resumes  its 
original  position  in  the  same  way  with  the  ease  and  grace  of 
motion  observed  in  a  bent  spring  when  the  force  has  been 
relieved.  Bone  resilience  is  readily  demonstrated  on  the 
skeleton  by  the  force  required  to  hold  the  fibula  against 
the  tibia.  When  the  clavicle,  detached  and  held  at  a  right 
angle  to  a  hard  surface,  is  struck  upon  the  end  with  a  ham- 
mer, it  will  rebound  to  a  distance  of  two  feet  or  more.  The 
equal  and  much  greater  concussion,  often  received  upon 
various  parts  of  the  body,  is  dissipated  and  lost,  on  account 
of  the  elasticity  of  bone,  before  reaching  the  delicate  organs 
enclosed.  The  relative  resistance  and  resilience  of  bone  is 
exhibited  in  the  experiment  of  Bloan,  who  found  that  a 
square  inch  of  it  (cross  section)  only  broke  under  a  load  of 
368-743  hundred- weight,  while  a  square  inch  of  copper  rod 
gave  way  under  340  and  of  Swedish  wrought-iron  under  648. 

Constancy  of  Chemical   Composition. 

So  admirably  are  the  organic  and  inorganic  matters 
blended  in  bone  to  secure  the  properties  and  subserve  the 
purposes  required,  that  any  variation  in  their  proportions 


160  CONSTANCY  OF  CHEMICAL  COMPOSITION. 

in  the  different  bones  of  the  same  animal,  or  at  different 
periods  of  life,  or  even  among  different  animals,  is  exceed- 
ingly small.  There  is  a  little  more  earthy  matter  in  the 
long  bones  of  the  extremities  than  in  those  of  the  trunk, 
and  a  little  more  in  the  larger  bones  of  the  extremities  than 
in  the  smaller,  but  the  increase  is  very  slight  and  is  in  no 
way  proportioned  to  the  density  or  hardness  of  bone,  which 
is  determined  solely  by  the  compactness  of  its  tissue.  Thus 
the  flexible,  semi-transparent,  easily  divided,  bones  of  the 
fish  contain  as  large  a  proportion  of  earthy  matter  as  the 
ivory-like  leg  bones  of  the  deer  or  sheep.  Bibra  found  the 
proportions  of  animal  and  earthy  matter,  contrary  to  the 
statements  usually  made,  very  nearly  the  same  in  the  bones 
of  the  foetus  of  seven  months,  in  those  of  a  man  of  thirty 
and  in  those  of  a  woman  of  seventy-eight,  and  Dr.  Stark 
concludes  from  his  numerous  analyses  "that  the  amount  of 
earthy  matter  in  healthy  bones  is  nearly  uniform  over  the 
whole  animal  kingdom;  and  that  neither  the  solidity  or 
sponginess,  the  rigidity  or  flexibility,  the  opacity  or  trans- 
parency of  bone  depends  on  an  increased  or  diminished 
amount  of  the  earthy  matters  in  its  composition."  It  is 
this  constancy  of  composition  which  justifies  the  belief 
that  the  union  of  the  animal  and  earthy  matters  is  not 
mechanical,  but  chemical. 

The  differences  in  the  bones  at  different  periods  of  life, 
usually  ascribed  to  variations  in  the  amount  of  earthy 
matter,  depend  entirely  upon  variations  in  the  amount  of 
bohe  substance,  not  at  all  upon  variations  in  its  physical 
construction.  A  foetal  bone  is  just  as  dense  and  as  hard  to 
cut  with  a  knife  as  an  adult  bone ;  it  is  more  flexible 
simply  because  there  is  less  of  it.  It  is  the  difference  be- 
tween a  little  stick  and  a  big  stick  of  the  same  wood.  The 
child's  bones  are  lighter  in  correspondence  with  its  nimble 
and   incessant    movements,    the    bones  of    the  adult  are 


RACHITIS  AND  OSTEOMALACIA.  1G1 

heavier  and  stronger  in  correspondence  with  the  force  of 
his  muscles,  and  the  old  man's  bones  are  lighter  again  in 
correspondence  with  his  slower  and  more  cautious  move- 
ments. But  the  difference  is  entirely  due  to  the  deposition 
and  absorption  of  bone  matter  in  correspondence  with  the 
general  nutritive  force.  A  fracture  of  a  child's  bone 
unites  more  rapidly  and  of  an  old  man's  bone  more  slowly, 
not  because  of  more  animal  matter  in  the  child  and  less  in 
the  old  man,  but  because  of  the  high  activity  of  nutrition 
in  youth  and  its  gradual  failure  in  advancing  age.  The 
difference  in  the  strength  of  bone  thus  induced  in  the  physi- 
ological decay  of  age  may  be  made  manifest  by  direct  ex- 
periment. Thus  a  prism  from  a  cross  section  of  the  fibula 
in  an  adult  aged  30  breaks  under  a  weight  of  33  lbs.  (15.03 
kilogrammes),  while  the  same  sized  prism  from  the  same 
bone  in  an  old  man  aged  74  breaks  under  a  weight  of  9}  lbs. 
(4.33  kilogrammes). 

Rachitis    and  Osteo-Malacia. 

There  are,  however,  certain  diseased  conditions  which 
very  greatly  disturb  the  proportions  of  animal  and  earthy 
matter  in  bone,  and  thus  lead  to  most  disastrous  deformities. 
In  rachitis  (rickets)  and  osteo-malacia,  for  instance,  both 
the  phosphate  and  carbonate  of  lime  are  often  reduced  to 
less  than  a  quarter  of  their  usual  quantities.  In  rachitis,  the 
mineral  salts  are  withheld  from  the  bone  in  the  blood.  In 
osteo-malacia,  these  salts  were  originally  deposited  but  have 
been  subsequently  absorbed.  Great  care  has  to  be  exercised 
with  rachitic  children,  as  the  bone  yields  to  every  pressure. 
Disfigurations  of  the  head  ensue  from  too  long  decubitus  in 
one  position,  and  deformities  of  the  pelvis,  such  as  in  after- 
life may  greatly  embarrass  the  accoucheur,  result  from  too 
long  support  of  the  child  in  one  posture  upon  the  arm  of 
the  nurse.     Fortunately,  this  disease,  which  is  an  expres- 

14 


162  THE   PHOSPHATE   OF   LIME. 

sion  of  innutrition,  is  very  rare  in  our  land  of  plenty.  In 
his  nutritive  experiments  upon  birds,  Chossat  found  in 
withholding  the  salts  of  lime  from  their  food,  that  not  only 
were  the  mineral  constituents  of  bone  diminished,  but  also 
the  animal.  All  the  ingredients  were  uniformly  lessened, 
and  in  progressive  inanition  the  per  cent,  constitution 
of  bone  undergoes  no  change. 

The  Phosphate  of  Lime. 

The  phosphate  of  lime  comes  to  be  selected  in  preference 
to  the  carbonate  in  the  manufacture  of  bone,  because  it 
forms  a  more  tenacious  compound  with  organic  matter. 
The  carbonate  is  far  more  abundant  than  the  phosphate  of 
lime  and  is  principally  used  in  the  construction  of  shell. 
Shell  is  very  fragile  and  brittle,  as  compared  with  bone, 
but  shell  is  not  subjected  to  the  same  demands  for  strength. 
Where  force  is  to  be  exerted  or  resisted,  as  in  the  vertebrate 
animals,  the  presence  of  animal  matter  becomes  a  necessity 
and  with  the  animal  matter,  the  phosphate  of  lime.  In  the 
hardest  of  all  animal  structures,  the  enamel  of  the  teeth, 
organs  which  lie  between  a  hammer  and  an  anvil,  as  it  were, 
the  phosphate  of  lime  is  present  in  the  proportion  of  over 
80  per  cent.  This  salt  must  be  furnished,  therefore,  in 
quantity  by  the  food.  Accordingly,  it  is  found  in  great 
abundance  in  the  nutritious  vegetables,  as  in  the  various 
cereal  grains,  for  which  it  furnishes,  in  turn,  the  most  valu- 
able manure.  The  drinking  water,  too,  however  pure  or 
soft,  always  contains  a  notable  quantity  of  the  salts  of  lime. 
Thus  Boussingault  observed  that  a  milk  cow  ingests  as 
much  as  an  ounce  (fifty  grammes)  of  mineral  water  per  day 
from  the  drinking  water  alone.  "By  causing  one  hundred 
head  of  cattle  to  drink  of  certain  potable  waters,  this  same 
observer  found  that  he  could  recover  yearly  from  their 
manure,  seven  to  eight  hundred  kilogrammes  (1540-1760  lbs.) 


THE  PRESERVATION  OF  BONE.  163 

of  mineral  salts  "eminently  useful  to  vegetation,"  among 
them  phosphorus,  sulphur,  chlorine,  silex  and  the  alkalies. 
It  is  a  point  of  extreme  physiological  interest,  the  fact  that 
of  all  the  albumenoids  used  as  food,  casein,  the  chief  con- 
stituent of  the  milk,  is  most  remarkable  for  the  large 
quantity  of  phosphate  of  lime  which  it  is  capable  of  holding 
bound  up  with  it,  and  the  tenacity  with  which  it  retains  it. 
The  rapid  growth  of  the  bones  during  infancy  receives,  thus, 
satisfactory  explanation. 

Preservation  of  Bone. 

The  intimate  union  of  the  animal  with  the  earthy  matter 
preserves  bone  from  decomposition  in  remarkable  degree. 
Thus  Bichat  found  that  clavicles  which  had  been  exposed 
for  ten  years  to  the  action  of  the  wind  and  rain  in  the 
cemetery  of  Clamant,  still  presented,  under  the  action  of  an 
acid,  an  abundant  cartilaginous  basis.  Orfila  relates  that 
the  bones  of  King  Dagobert,  exhumed  from  St.  Denis  after 
1200  years,  were  still  preserved.  This  distinguished  chemist 
actually  obtained  as  much  as  27  per  cent,  of  gelatine  from 
bones  known  to  have  been  600  years  old.  Liman  states  that 
he  is  in  possession  of  an  ulna  which  was  dug  up  in  Pompeii 
in  1844,  in  the  presence  of  Casper,  from  ashes  in  which  it 
had  lain  for  nearly  1800  years,  in  such  perfect  preservation 
that  it  may  still  be  used  for  purposes  of  anatomical  demon- 
stration. Davy  found  in  a  frontal  bone  exhumed  from 
Pompeii  35}  per  cent,  organic  and  64}  per  cent,  mineral 
matter,  and  Haller  claims  to  have  obtained  gelatine  from  the 
bones  of  a  mummy  2000  years  old.  But  what  are  these 
insignificant  periods  of  time  to  the  geological  eras  which 
have  elapsed  while  bone  has  been  still  preserved  ?  Fossil 
bones,  long  antedating  the  existence  of  man  upon  earth, 
are  often  found  to  exhibit  the  same  true  proportions  of 


164  BONE,   A  CONNECTIVE  TISSUE. 

animal  and  mineral  matter.     Thus  Davy  found  in  the  tooth 
of  a  mammoth  30.5  parts  animal  to  69.5  mineral  matter. 

Bone,  a  Connective  Tissue. 

Notwithstanding  its  great  importance,  bone  does  not 
belong  to  the  primary  or  original  tissues  of  the  body. 
Many  of  the  remaining  tissues  are  far  advanced  in  develop- 
ment before  bone  puts  in  any  appearance  at  all.  Bone 
belongs  to  the  group  of  connective,  or,  as  Kolliker  has 
better  put  it,  the  "sustentacular"  tissues,  but  a  subsequent 
transformation  or  elaboration  of  this  tissue  is  required  to  de- 
velop bone.  As  any  connective  tissue  may  ossify,  bone  some- 
times appears  in  strange  and  unwonted  places.  The  skin,  the 
fibrous  membranes  (dura  mater),  the  tendons,  the  sclerotic 
coat  of  the  eye,  are  naturally  partly  bony  or  contain  bone 
in  some  of  the  lower  animals  and  bone  not  unfrequently 
presents  in  these  structures  in  man.  Thus  my  colleague 
Dr.  W.  W.  Seely  exhibited  to  the  Cincinnati  Academy  of 
Medicine  an  eye-ball  which  he  had  removed,  containing  a 
capsule  of  bone  covering  the  entire  inner  surface  of  the 
choroid  coat  of  the  eye  and  referred  to  a  case  on  record  in 
which  there  was  a  complete  globe  of  bone  covering  the  choroid 
and  extending  across  behind  the  lens.  Most  melancholy 
are  the  cases  of  so-called  myositis  ossificans  progressiva,  in 
which  the  inter-muscular  connective  tissue  is  converted  into 
true  bone,  locking  up  the  action  of  the  muscles  as  fatally  as 
in  the  fabled  metamorphoses  of  Ovid.  Cases  of  this  terrible 
disease  has  been  put  upon  record  by  Rogers,  Henry,  Skinner 
and  Nikoladoni  and  our  demonstrator  of  anatomy, 
Dr.  Iiansohoff,  gives  in  detail  in  a  recent  number  of  The 
Lancet  and  Clinic  an  account  of  a  case  which  fell  under  his 
personal  observation,  where  "the  process  of  placing 
the  patient  on  his  feet  involuntarily  suggested  that 
of    placing    a    statue    upon    its   pedestal."     Most  of    the 


TILE  FORMATION   OF   BONE.  105 

cases  of  so-called  ossifications  of  soft  parts,  however 
(as  in  the  larynx,  the  heart,  etc.),  turn  out  to  be  simple 
calcifications  (infiltrations  with  mineral  salts),  a  very  inferior 
process  to   the   development  of   true   bone. 

The  Formation  of  Bone. 

For  the  most  part,  bone  is  formed  from  cartilage.  It  is 
more  true  to  say  that  bone  is  formed  in  cartilage,  for  the  car- 
tilage that  is  to  result  in  bone  must  entirely  disappear 
before  bone  tissue  can  develop.  The  inter-cellular  spaces 
in  cartilage  dissolve  away,  leaving  medullary  canals,  and 
the  cartilage  cells  become  enclosed  in  lime  salts  (calcined) 
as  the  first  step  in  the  process  of  ossification.  Then  the 
calcified  cartilage  itself  undergoes  liquefaction  and  young 
formative  cells  (probably  lymphoid  cells  of  the  blood), 
emigrated  from  advancing  bloodvessels,  penetrate  the 
cartilage  cavities  to  become,  some  of  them  at  least,  genera- 
tors of  the  osseous  tissue.  These  "osteoblasts,"  as  they  are 
now  called ;  later,  they  are  the  stellate  bone  cells ;  secrete 
from  their  interior  a  thin  layer  of  homogeneous,  opalescent 
matter,  which  is  subsequently  infiltrated  with  the  salts  of 
lime,  to  constitute  the  first  layer  (lamella)  of  true  bone 
tissue.  A  repetition  of  this  process  produces  the  successive 
layers  or  strata  of  bone  about  the  bloodvessels,  now  known 
as  the  Haversian  canals. 

The  vessels  in  the  membrane  enveloping  bone,  the  peri- 
osteum, which  is  at  first  highly  vascular,  likewise  furnish 
osteoblasts  for  the  development  of  successive  layers  of  bone 
about  its  circumference. 

There  is,  however,  some  exception  to  the  rule  that  bone 
is  moulded  first  in  cartilage.  For  the  flat  cranial  bones, 
the  upper  and  lower  jaw,  the  nasal,  lachrymal  and  palate 
bones,  the  vomer,  zygoma  and  finally  the  inner  leaf  of  the 
wings  of  the  sphenoid  and  the  cornua  sphenoidalia,  in  short, 


166  THE   TEllIOSTEUM. 

many  of  the  bones  of  the  face  and  all  the  bones  of  the  head 
(except  the  base  of  the  occipital  bone,  which  is  often  described 
as  a  separate  bone  belonging  to  the  spinal  column),  develop 
from  membrane,  that  is,  from  the  periosteum  or  pericranium 
in  the  site  of  the  future  bone.  In  all  cases,  however,  the 
process  is  essentially  the  same. 

So  active  is  the  power  of  the  periosteum  in  the  production 
of  bone  that  the  endeavor  is  always  made  by  the  surgeon  to 
save  it  as  much  as  possible  in  exsectionsof  dead  bone  tissue- 
Great  masses  of  bone,  the  entire  clavicle  for  instance,  may 
be  reproduced,  if  the  under  (generating)  layer  of  periosteum 
be  left  uninjured.  Indeed,  Oilier  has  found  that  pieces  of 
periosteum  transplanted  from  one  part  to  another  or  from 
one  animal  to  another  will  beget  bone  even  in  places  where 
it  must  be  regarded  as  a  foreign  body. 

The  Periosteum. 

The  bones,  thus,  do  not  lie  naked  in  the  body.  They  are 
all  clothed  with  a  dense  fibrous  membrane,  the  periosteum, 
which,  in  the  first  place  produces  the  bone  tissue,  or  repro- 
duces it  after  injury,  from  its  under  surface,  and  then, 
thickening  as  the  bone  develops,  isolates  and  protects  it 
from  circumjacent  tissues.  The  periosteum  thus  acts  as  a 
barrier  against  the  invasion  of  disease.  The  shin  bone,  for 
instance,  is  long  protected  against  damage  from  the  so 
frequent  and  so  extensive  ulcers  of  the  leg.  In  cases  where 
the  periosteum  is  scant  or  insufficient  to  cover  the  entire 
surface,  superficial  inflammations  easily  dip  down  to 
involve  the  underlying  bone.  That  the  slightest  wounds  or 
contusions  of  the  ends  of  the  ringers  may  extend  to  the 
insufficiently  covered  bone  beneath  is  proven  by  the  frequent 
occurrence  of  those  painful  affections  known  as  whitlows  or, 
with  us,  as  felons.  Hence  the  advantage  of  free  and  early 
incision  in  their  treatment  to  permit  escape  of  the  products 


THE   DETERMINATION   OF   AGE.  167 

of  inflammation.  Lastly,  the  periosteum  is  a  surface  sheet 
of  fibrous  tissue  wrapped,  as  it  were,  about  the  bone  to  give 
firm  origin  and  fixed  insertion  to  muscles,  ligaments  and 
tendons. 

The  Centre  of  Ossification. 

The  point  at  which  the  osteoblasts  begin  to  form  and 
from  which  the  bone-making  process  irradiates  to  the  whole 
structure  is  known  as  the  "centre  of  ossification."  But  the 
period  of  time  at  which  this  centre  appears  does  not  at  all 
correspond  to  the  deposition  of  the  primordial  cartilage 
in  the  site  of  the  future  bone.  Thus  the  cartilage  of  the 
vertebra,  the  so-called  notochord  or  chorda  dorsalis,  appears 
in  the  earliest  days  or  weeks  of  development,  while  the  first 
points  of  ossification  show  themselves  about  the  beginning 
of  the  second  month  almost  simultaneously  in  the  clavicle 
and  lower  jaw. 

The  Determination  of  Age. 

As  the  exact  period  of  time  in  which  ossification  com- 
mences in  the  various  bones,  and  the  rate  at  which  it  ad- 
vances, have  been  definitely  ascertained,  it  may  be  readily 
understood  that  we  possess  in  such  data  the  means  for  accurate 
estimate  of  the  age  of  the  bones  or  of  the  body.  Beale  has 
discovered  that  immersion  of  the  body  of  the  foetus,  or  the 
new  born  child,  in  alcohol  and  soda  (8  to  10  drops  of  solution 
of  caustic  soda  to  the  ounce  of  alcohol)  renders  the  soft  parts 
so  translucent  or  transparent,  without  affecting  the  earthy 
matter,  that  the  stage  of  ossification  in  the  different  bones 
becomes  at  once  visible  to  the  eye. 

Or  the  age  may  be  determined  by  the  size  or  length  of  the 
bones.  Giinz  has  carefully  prepared  for  this  purpose  a  table 
of  the  dimensions  of  the  various  bones  at  birth. 


168  THE   FEMORAL  EPIPHYSEAL   CENTRE. 

The   Femoral  Epiphyseal    Centre. 

But  the  readiest  method  of  deciding  the  question  of 
maturity  at  birth,  a  question  of  great  importance  from  a 
forensic  point  of  view,  was  first  established  by  Beclard,  and 
subsequently  elaborated  by  Ollivier,  Hartmann  and  Mild- 
ner.  These  investigators  found  that  the  most  reliable  sign 
of  an  advanced  process  of  ossification  was  the  presence  of  a 
"centre"  in  the  lower  end  (epiphysis)  of  the  femur.  This 
centre  develops  in  the  second  half  of  the  last  month  of  preg- 
nancy, before  the  existence,  thus,  of  any  epiphyseal  centre 
in  any  other  long  bone  of  the  body.  Section  of  the  epiphy- 
seal cartilage  of  this  bone  discloses  to  the  unaided  eye,  in 
the  centre  of  the  milk-white,  cartilaginous,  mass,  a  more  or 
less  circular,  bright,  blood-red,  disk,  whose  density  easily 
distinguishes  it  as  bone  in  the  softer  tissue  about  it.  The 
comparative  imperishability  of  bone  makes  this  sign  all  the 
more  valuable,  as  it  may  always  be  discovered  though  de- 
composition of  the  remaining  structures  shall  have  been  far 
advanced.  In  such  cases  it  loses  its  bright  red  color,  be- 
coming of  a  dirty  yellow  hue,  but  it  still  stands  prominently 
forth  and  differentiates  itself  from  the  surrounding  decom- 
posing, reddish,  matter  by  its  color  and  its  hardness.  Once 
seen,  it  will  be  always*  recognised  again.  In  very  small 
bones,  it  must  be  hunted  out  with  a  lens,  but  in  bones  of 
average  size,  it  is  plainly  visible  to  the  eye.  Li  man  states, 
as  the  result  of  G20  observations,  that  the  presence  of  this 
nucleus  of  bone,  with  a  diameter  of  over  nine  millimetres 
(4  lines),  is  the  most  unmistakable  proof  that  the  child  was 
born  mature.  A  less  diameter  (3  lines)  would,  of  course, 
not  disprove  maturity  at  birth,  as  the  bones  in  some  indi- 
viduals are  unusually  small.  Cases  are  narrated  by  Liman 
and  Ollivier  where  decomposed  and  mummified  parts 
only  were  found,  and  yet  maturity  at  birth  was  thus 
established. 


THE  EXCAVATION   OF   BONE.  169 

The   Excavation   cf  Lone. 

As  bone  grows  upon  its  exterior  it  is  absorbed  from  the 
interior  of  its  mass.  This  process  of  interior  absorption  oc- 
curs in  all  bones  alike,  regardless  of  their  size,  or  shape  or 
use.  Thus  the  bones,  in  all  cases  solid  at  first,  become 
hollowed  out  inside.  In  the  long  bones,  a  great  cavity  (the 
medullary  cavity)  results,  in  the  flat  and  irregular  bones,  a 
multitude  of  small  communicating  chambers.  This  spongy 
or  cancellated  tissue  left  by  the  absorption  of  the  bone  has, 
of  course,  the  same  texture  and  composition  as  the  still 
compact  external  layer.  But  its  physical  properties  differ. 
That  is,  it  is  lighter  and  softer,  and  hence  is  better  fitted  to 
resist  and  disperse  force.  Yet  the  whole  bone  loses,  in  this 
loss  of  substance,  little  or  none  of  its  strength.  For  the 
long  bones  are  thus  converted  into  tubular  structures,  and 
every  one,  familiar  with  mechanics,  is  aware  of  the  greater 
strength  of  the  same  amount  of  substance  arranged  in 
tubular  over  that  in  solid  form.  The  flat  bones,  as  in  the 
cranium,  become,  thus,  three  tables,  of  which  the  outer  and 
inner  are  compact,  and  the  central,  the  diploe  (from  61a,  -kIeu 
to  fill  through,  not  from  6i~7,oog  double),  is  spongy  tissue. 
The  excavation  of  bone  tissue  in  this  way,  the  stuffing  of  it, 
as  it  were,  with  resilient  tissue,  aided,  of  course,  by  the 
general  arched  form  of  the  bone,  so  disseminates,  lateralises 
and  absorbs  shocks,  in  the  case  of  the  cranium,  for  instance, 
that  the  brain  is  seldom  injured  by  a  force  insufficient  to 
crack  the  skull.  The  irregular  collection  of  seven  or  eight 
obliquely  moulded,  soft,  bones  at  the  wrist  and  ankle,  bound 
so  firmly  together  by  ligaments  as  to  practically  be  one 
bone,  and  yet  movable  enough  to  permit  wide  range  of 
motion,  is  an  admirable  example  of  the  advantage  of  can- 
cellated structure  in  dissipating  shocks  as  received  upon  the 
hands  and  feet.  The  jaw  bones,  at  their  free  edges,  would 
be  chipped  away  under  the  chopping  and  grinding  action  of 

15 


170  AIR  IN  BONE. 

the  teeth,  were  it  not  for  the  cushion  of  spongy  tissue  (the 
alveolae)  in  which  the  teeth  are  embedded. 

But  this  interior  absorption  of  bone  does  not  occur  in  a 
hap-hazard  way.  If  a  long  bone,  for  instance,  be  split  in 
two,  lengthwise,  it  will  be  seen  that  the  spongy  tissue  is 
arranged  in  a  definite  manner,  that  is,  that  the  individual 
layers  of  bone,  thus  resulting,  run  in  definite  directions. 
Such  directions  are  most  markedly  manifest  about  the 
heads  and  extremities  of  the  long  bones.  The  interior 
plates  here  form  pillars,  arches,  buttresses,  braces,  so  con- 
structed as  to  most  effectually  receive  and  transmit  weight 
from  the  articular  surfaces  to  the  compact  tissue  of  the 
shaft.  This  architecture  of  bone,  as  it  is  called,  has  re- 
ceived able  exposition  at  the  hands  of  a  number  of  observers, 
Wolfmann,  Meyer,  and  others,  in  terms  of  highest  admira- 
tion. Indeed,  the  internal  architecture  of  bone  was  at^one 
time  triumphantly  singled  out  as  an  evidence  of  design  in 
creation.  It  is  hardly  necessary  now  to  state  that  natural 
selection  achieves,  in  the  courses  of  ages,  the  highest  order 
of  design. 

Air   in   Bone. 

The  excavation  of  the  interior  of  bone  secures  to  bones 
their  lightness.  Hence  it  meets  its  highest  expression  in 
birds,  where  the  number  of  bones  into  which  air  is  admitted 
is  directly  proportionate  to  the  powers  of  flight.  When  the 
trachea  is  tied  in  some  birds,  respiration  may  be  sustained 
for  a  time  through  an  aperture  made  in  the  arm  (wing) 
bone.  Thus,  in  the  swift,  air  finds  its  way  into  most  of  the 
bones ;  whereas  in  the  ostrich  and  its  allies,  the  shafts  of  the 
long  bones  are  partly  occupied  by  spongy  tissue,  and  in  the 
apteryx,  none  of  the  bones  receive  any  air  at  all  (Humphrey). 
In  fishes,  supported  as  they  are,  by  water,  all  the  bones  are 
solid,  as  they  are  during  the  aqueous  (intra-uterine)  stage 


THE   MARROW.  171 

of  life  in  man.  The  facial  bones  in  all  mammals  (including 
man)  are  mere  shells  filled  with  air  for  the  sake  of  lightness. 
The  suppression  of  these  bones  in  man  to  give  range  and 
prominence  to  the  higher  organs  of  sense,  and  their  com- 
parative lightness  are  distinguishing  characteristics  of  the 
human  skull  and  skeleton  to  secure  the  vultus  ad  sidera. 

The  Marrow. 

The  next  lightest  medium  to  air  is  oil.  Hence  we  find 
the  bones  of  most  land  animals  filled  with  liquid  fat.  The 
long  bones  of  the  adult  contain  a  marrow  of  which  96  parts  are 
oil.  Large  reservoirs  are  thus  inserted  in  the  body,  of  this 
highly  nutritious  substance,  upon  which  draft  is  made  in  in- 
sufficient alimentation  or  inanition  from  any  cause.  The 
quantity  of  oil  present  in  the  bones  is  thus  indicative  of  the 
health  and  vigor  of  the  body ;  hence  the  force  of  the  com- 
ment of  Job  upon  a  man  in  the  prime  of  his  strength,  "his 
bones  are  moistened  with  marrow."  Timon  of  Athens 
says  "consumptions  sow  in  hollow  bones  of  man,"  and  Lucio 
(Measure  for  Measure)  remarks  upon  the  effects  of  chronic 
syphilis  in  the  accusation  "thy  bones  are  hollow ;  impiety 
has  made  a  feast  of  thee."  It  has  occasionally  happened,  as 
an  anomaly  of  development,  that  this  process  of  internal 
absorption  of  bone  has  not  taken  place.  The  bone  then  re- 
mains solid  (compact)  throughout.  The  celebrated  anato- 
mist of  Holland,  Frid.  Ruysch,  is  said  to  have  possessed  a 
fork  whose  handle  had  been  turned  from  a  solid  human 
bone. 

Studies  in  Living  Bone. 

In  our  studies  of  bone,  dead  and  dried,  as  in  anatomical 
specimens,  we  are  apt  to  forget  that  bone  in  the  body  lives. 
Bone  is  as  much  alive  as  brain  or  blood.  It  absorbs, 
breathes,   secretes  and  reproduces  itself  like  every  other 


172  STUDIES  IX   LIVING   BONE. 

living  tissue.  It  has  been  shown  by  Oilier  that  so  long  as 
bone  tissue  retains  its  vitality,  it  may  be  removed  from  one 
animal  to  another,  or  be  transplanted  to  A'arious  parts  of  the 
same  animal,  and  not  only  continue  to  live,  but  also  increase 
in  bulk. 

The  absorptive  power  of  bone  is  elegantly  exhibited  by 
feeding  animals  with  coloring  matter  having  an  affinity 
for  the  phosphate  of  lime.  It  was  long  ago  accidentally 
discovered  by  Belchier  that  madder  fed  to  pigs  imparts  its 
color  to  the  bones.  If  the  animal  be  very  young,  the  whole 
skeleton  may  be  thus  colored  in  a  single  day.  In  older 
animals,  the  coloration  is  more  slow  and  less  perfect,  only 
the  growing  parts  of  the  bone,  as  at  the  ends  and  surface, 
assuming  color.  Periodically  administered  and  withheld,  it 
produces  alternate  layers  of  red  and  white.  Belchier  first 
used  this  agent  as  a  means  of  studying  the  growth  of  bone, 
and  Tomes  prepared  beautifully  colored  specimens  in  this 
way.  That  long  bones  grow  in  length  only  at  the  ends, 
after  ossification  of  the  shaft,  was  conclusively  proven  by 
the  experiments  of  Hales  and  Hunter,  who  inserted  into  the 
shafts  metallic  substances,  certain  distances  apart,  and 
found,  after  an  interval  of  time,  that  the  distance  between 
them  remained  the  same,  while  the  extremities  of  the  bones 
wTere  much  further  apart.  And  that  bone  grows  upon  its 
surface  and  is  hollowed  out  in  its  interior,  was  as  conclu- 
sively proven  by  du  Hamcl,  who  put  a  silver  ring  on  one  of 
the  long  bones  of  a  pigeon,  and  found  it  later  in  the 
medullary  cavity,  which  had  the  same  diameter  as  the  ring. 

Use  and  disuse  exercise  the  same  influence  upon  bone  as 
upon  other  living  tissues.  Bones  increase  both  in  thickness 
and  length  when  called  upon  to  support  heavier  weights. 
Different  occupations  vary  the  size  of  the  bones  iu  all  direc- 
tions. These  variations  are  exemplified  in  the  osseous 
changes  manifesting  themselves  upon  the  domestication  of 


STUDIES  IN  LIVING  BONE.  173 

wild  animals.  The  leg  bones,  under  conditions  of  security 
and  plenty,  greatly  increase  in  size,  while  the  wing  bones 
diminish.  The  legs  of  sailors  employed  in  the  late  war  were 
longer  by  0.217  of  an  inch  than  those  of  the  soldiers; 
though  the  sailors  were,  on  an  average,  shorter  men ;  while 
their  arms  were  shorter  by  1.09  of  an  inch,  and  therefore 
out  of  proportion  shorter,  in  relation  to  their  lesser  height. 
Bengger  attributes  the  thin  legs  and  thick  arms  of  the 
Payaguas  Indians,  to  successive  generations  having  passed 
their  whole  lives  in  canoes  with  their  lower  extremities 
motionless.  Darwin,  in  his  Descent  of  Man,  from  which 
work  these  examples  are  cited,  gives  abundant  evidence  ex- 
hibiting the  changes  occurring  in  different  bones  under 
different  conditions.  Thus  in  long-eared  rabbits,  even  so 
trifling  a  cause  as  the  lopping  forward  of  one  ear,  drags  for- 
ward on  that  side  almost  every  bone  of  the  skull ;  so  that 
the  bones  on  the  opposite  side  no  longer  strictly  correspond. 
The  life  of  bone  is  strikingly  shown  in  the  absorptive 
changes  which  ensue  upon  long  continued  pressure.  The 
flat  heads  of  Indians,  short  feet  of  Chinese,  and  bent  ribs  of 
more  civilized  races,  are  all  proofs  of  the  yielding  of  bone 
under  distorting  pressure.  Not  very  long  ago,  a  case  was 
reported  in  Vienna,  where  a  young  girl  died  of  inflamma- 
tion of  the  brain  caused  by  the  long  continued  and  gradually 
tightening  pressure  of  an  elastic  cord  used  to  confine  a  net 
for  the  hair.  The  cord  had  absolutely  cut  through  the 
cranium  to  the  brain. 

Quite  recently,  M.  Oilier  has  shown  that  it  is  possible,  by 
irritating  the  ends  of  bones,  or  the  periosteum  upon  their 
surface,  to  greatly  alter  their  size  and  shape.  We  may  thus 
secure,  he  claims,  a  harmony  of  development  between  two 
parallel  bones,  on  the  one  hand,  by  increasing  the  activity 
of  development  of  the  bone  in  arrears,  on  the  other,  by  re- 
tarding or  checking  the  development  of  the  bone  in  excess. 


174  BONE  AS  A  SYMBOL  OF  THE  BODY. 

Nothing,  however,  has  so  much  elevated  the  physiological 
dignity  of  bone  as  the  recent  revelations  of  Neumann  and 
Bizzozero,  to  the  effect  that  a  vast  number  of  the  blood 
corpuscles,  the  most  essential  element  of  this  most  essential 
fluid,  are  developed  in  the  marrow  of  bone.  These  observers 
have  discovered  in  the  marrow  all  the  transition  forms 
between  the  white  lymph  corpuscles  and  the  red  blood  cor- 
puscles, so  that  bone  comes  to  rank  with  the  liver  and  the 
spleen  as  one  of  the  cradles  in  the  rearing  of  the  blood. 

Bone  is  often  used  as  a  symbol  of  the  whole  body. 
"Flesh  of  flesh  and  bone  of  bone"  is  the  phrase  used  to  ex- 
press the  intimacy  of  the  conjugal  union.  "Was  not  from  a 
rib  in  the  same  symbolic  sense  developed  the  whole  female 
body  ?    Schiller  says  jestingly : — • 

"Behandelt  die  Frauen  mit  Nachsiclit! 
Aus  krumraer  Rippe  war  sic  erschaffen, 
Gott  konnte  sie  nicht  ganz  grade  machen, 
Willst  du  sie  biegen,  sie  bricht." 

(Handle  a  woman  with  care! 
She  was  made  from  a  crooked  rib, 
God  could  not  make  her  perfectly  straight, 
If  you  bend  her,  she  will  break.) 

But  it  was  reserved  for  M.  Frederic  de  Rougemont, 
a  distinguished  theologian,  to  solemnly  announce  a 
satisfactory  reason  why  "God  in  his  infinite  wisdom 
selected  the  rib  in  preference  to  any  other  bone  of  Adam's 
body."  He  says:  "Pie  took  no  piece  of  the  head — woman 
would  then  have  had  too  much  intelligence ;  He  took  no 
piece  of  the  legs — woman  would  then  have  been  too  much 
on  the  move ;  He  took  a  piece  near  the  heart,  that  woman 
should  be  all  love  !"     Gretchen  sings  in  her  utter  desolation : 

?  Wcr  fuhlet 

Wie  wtihlet 

Dcr  Schmerz  mir  im  Gebein. 

(Who  fcc!s,  how  rages,  the  pain  in  my  bones.) 


MUSCLE   AND   ITS  PROPERTIES.  175 

Agamemnon  (Troilus  and  Cressida)  is  addressed  :— 

"Thou  great  commander,  nerve  and  bone  of  Greece." 

and  when  Achilles,  later  in  the  same  play,  wished  to  express  in 
the  death  of  Hector,  the  total  overthrow  of  Troy,  he  exclaims : 

"Now  Troy  sink  down, 
Here  lies  thy  heart,  thy  sinew  and  thy  bone." 


LECTURE    IX. 


MUSCLE  AND  ITS  PROPERTIES. 

CONTENTS. 

Etymology  of  Muscle — Muscular  Motion — Striped  and  Smooth  Muscle 
— The  Color  of  Muscle — The  Anatomy  of  Voluntary  Muscle — The 
Sarcolemma — The  Muscle  Fibre — Muscle  Protoplasm — General  Prop- 
erties of  Muscles — Names  of  Muscles — Form  and  Shape  of  Muscles — 
Smooth  Muscle— Disposition  of  Smooth  Muscle — The  Chemistry  of 
Muscle — The  Reaction  of  Muscle — Specific  Properties  of  Muscle — 
The  Elasticity  of  Muscle — The  Tonicity  of  Voluntary  Muscle — 
Tonicity,  a  Reflex  Phenomenon — Tonicity  of  Involuntary  Muscle — 
The  Sensibility  of  Muscle — Sensibility  and  Sensation — The  Sensation 
of  Fatigue — The  Exercise  of  the  Muscular  Sense. 

Etymology  of  Muscle. 

The  muscles  are  the  active  organs  of  motion.  The  word 
bone  (Saxon,  ban ;  Swedish,  ben ;  Danish,  been ;  German, 
bein),  means  something  set  or  fixed.  The  word  muscle 
(Latin,  musculus)  originates,  according  to  some  etymologists, 
from  [j.vr,  a  mouse  or  rat,  because  the  ancients  compared  the 
muscles  to  flayed  rats  or  mice,  but  is  more  probably  derived 
from  (iveiv,  to  move,  motion  being  the  most  striking  and  dis- 
tinguishing property  of  this  tissue.  Brawn,  an  old  English 
synomim.  of  muscle,  expressed  the  fact  that  the  bulk  and 


170  MUSCULAR  MOTION. 

strength  of  the  body  was  expressed  or  made  manifest  in  its 
flesh  or  muscle. 

Muscular  Motion. 

Though  the  mere  existence  of  motion  can  not,  as  once 
taught,  be  accepted  as  a  point  of  differentiation  between 
animals  and  plants,  because  it  is  a  protoplasmic  endowment 
common  to  both,  nevertheless  a  high  degree  of  it  and  a 
ready  exhibition  of  it  does  distinguish  animals  high  in  the 
scale  of  development.  All  visible  motion  is  produced  solely 
by  the  action  of  muscles.  The  complicated  movements  of 
the  higher  forms  of  animal  life  require  a  great  number  of 
muscles,  properly  disposed  and  adjusted  in  their  arrange- 
ment, quickly  responsive  in  their  action,  and  nicely  poised, 
coordinated,  and  antagonised,  in  their  effect.  In  man  there 
are,  subject  to  the  control  of  his  will,  over  one  thousand 
muscles,  whose  mass  constitutes  half  the  bulk  or  volume  of 
the  body. 

Besides  these  so-called  voluntary  muscles,  this  tissue  in 
the  form  of  fibres  or  layers  enters  into  the  composition  of 
nearly  all  the  organs  of  the  body  connected  with  the  vege- 
tative life.  The  digestive,  respiratory,  circulatory,  genito- 
urinary, etc.,  systems  are  in  part  constructed  of  muscular 
tissue  whose  insensible  action  is  involuntary,  that  is,  beyond 
the  control  of  the  will. 

Striped  and  Smooth  Muscle. 

The  voluntary  are  readily  distinguished  from  the  in- 
voluntary muscles  under  the  microscope  by  the  fact  that 
the  voluntary  muscle  fibres  are  striped  while  the  involuntary 
are  smooth.  Yet  there  are  some  exceptions  to  this  rule. 
The  muscle-substance  of  the  heart,  for  instance,  is  striped, 
though  its  action  is  entirely  beyond  the  control  of  the  will, 
as  Is  also  that  of  the  pharynx,  of  the  rectum  and  urethra. 


THE   COLOR   OF   MUSCLE.  177 

Wherever  promptitude  of  response  and  power  of  contrac- 
tion is  needed  the  muscular  tissue  is  always  striped,  whether 
voluntary  or  not. 

In  man  and  the  higher  vertebrates  these  two  varieties  of 
muscular  tissue  are  distinctly  separated,  but  in  the  lower 
vertebrates,  and  still  more  markedly  in  invertebrates,  transi- 
tion forms    occur.     In   the    echinodermata  (star-fish,  sea- 
urchins,  etc.),  all  the  fibres  are  smooth,  as  also,  in  the  rule,  in 
the  molluscs.     In   the  helminths  the  muscular  fibres  are 
almost  always  smooth,  the  only  instance   of  striped  muscle 
existing,  strange  to  say,  not  in  the  apparatus  of  locomotion, 
but  in  the  uterus  of  the  echinorhynbhus  nodulosus  (Leydig). 
It  should  be  stated  also  in  this  connection  that  some  fibres 
which  were  formerly  regarded  as  smooth  are  now  known  to 
be  striped.     Thus  Margo  discovered  that  the  closing  muscle 
of  the  bivalves,  hitherto  described  as  unstriped,  under  high 
magnification  and  fine  definition,  distinctly  exhibits  very 
fine  stride  or  stripes.     And  that  the  marked  degree  of  differ- 
ence formerly  attached  to  the  histological  division  of  muscu- 
lar tissue  no  longer  holds  good  is  evidenced  by  the  fact, 
reported  by  Vierordt,  that  the  same  organ  in  different  ani- 
mals has  sometimes  striped  and  sometimes  smooth  fibres  to 
accomplish  the  same  purpose.     In  the  body  of  man,  the 
heart,  whose  action  is  involuntary,  is  composed  of  striped 
muscle,  while  the  accommodation  of  vision  for  objects  at 
different  distances,  a  voluntary  act,  is  effected  by  the  un- 
striped, involuntary,  choroid  muscle. 

The  Color  of  Muscle. 

The  deep  red  color  of  striped  muscle,  is  partly  due  to 
the  blood  which  circulates  throughout  its  substance,  in  a 
rectangular  network  of  capillaries,  whose  distribution  is 
among  the  finest  in  the  body.  The  cruel  custom  prevailed 
among  butchers,  formerly  more  extensively  than  now,   of 


178  THE  SARCOLEMMA. 

subjecting  young  animals,  calves,  etc.,  to  frequent  bleedings 
before  final  slaughter  in  order  to  render  the  flesh  more 
tender.  The  butchers  were  said  to  "bleed  the  animal 
white"  as  the  muscle  thus  became  much  paler  in  hue,  but 
no  abstraction  of  blood  will  make  muscle  absolutely  color- 
less. Even  though  a  muscle  be  washed  free  of  blood 
outside  of  the  body,  or  water  be  injected  into  its  vessels 
until  it  escapes  colorless,  the  muscle  substance  will  still 
preserve  a  distinct  amber  hue,  which  may  be  regarded  as  the 
intrinsic  color  of  muscle  protoplasm.  Kolliker  observes 
that  the  color  of  muscle  is  duetto  the  presence  of  a  coloring 
matter  analogous  to,  but  independent  of  that  of  the  blood, 
and  Fremy  has  given  to  this  peculiar  yellow  coloring 
matter,  in  the  case  of  the  salmon  and  other  fish,  the  name, 
salmonic  acid.  Kiihne  and  Eanvier  washed  out  red  muscles 
with  "artificial  serum"  (a  half  percent,  solution  of  common 
salt)  and  established  the  fact  that  the  color  of  muscle  is  not 
due  to  the  presence  of  blood,  but  to  haemoglobin. 

The  Anatomy  of  Voluntary  Muscle. 

Striated  muscles,  of  the  size  and  shape  adapted  for  the 
special  purpose,  consist  of  bundles,  fasciculi,  aggregated  in 
mass,  and  enveloped  in  firm  but  elastic  sheets  of  connective 
tissue,  which  also  sends  in  partitions  to  surround  the  smaller 
bundles  within.  These  smaller  bundles,  with  intervening 
bloodvessels,  connective  tissue,  and  fat  masses,  are  distinctly 
visible  on  cross  section  of  a  muscular  mass.  In  longitu- 
dinal separation  of  the  bundles,  we  finally  arrive  at  the 
ultimate  muscular  fibre,  with  its  investing  sheet  of  connec- 
tive and  elastic  tissue,  the  sarcolemma. 

The  Sarcolemma 

forms  both  the  dura  and  pia  mater  of  the  muscular  fibre 
in  that  by  its  density  it    contains  the  diffluent  muscle 


THE  MUSCLE   FIBRE.  179 

protoplasm  arid  restrains  it  from  undue  dissemination,  by 
its  surface  it  gives  space  for  the  rich  network  of  vessels 
to  convey  the  blood  needed  in  such  abundance  for  muscle 
work  ;  then  by  its  elasticity  it  greatly  economises  muscular 
force.  The  transparent,  homogeneous,  closely  adherent, 
sarcolemma  or  primitive  sheath  is  readily  exhibited  by 
forcibly  breaking  the  fibre  in  two,  continuity  being  still 
maintained  by  the  firm,  though  delicate  sheath.  On  long 
maceration  in  water  the  sarcolemma  is  raised  in  blisters 
(blebs)  upon  the  surface  of  the  fibre. 

The  Muscle  Fibre. 

The  muscle  fibre  itself  is  one  of  the  most  complex  struc- 
tures in  the  animal  economy.  By  long  maceration  in  water 
or  alcohol,  or  more  especially  in  solutions  of  the  bichromate 
of  potash,  it  splits  up  into  3-500  finer  fibrilla3  running 
parallel  with  each  other  throughout  the  length  of  the  fibre. 
By  maceration  in  very  dilute  hydrochloric  acid  or  in  gastric 
juice  it  separates  into  transverse  disks  with  complete  ob- 
literation of  the  longitudinal  markings  of  the  fibrillse.  It  is 
a  question  still  unsettled  as  to  which  of  all  these  structures, 
the  fiber,  the  fibrilla  or  the  disk  is  the  ultimate  anatomical 
element.  If  the  muscle  tissue  be  separated  in  both  direc- 
tions, transversely  and  longitudinally,  it  is  divided  into 
minute  rectangular  prisms  or  caskets,  and  in  sections  of 
frozen  muscle  the  outlines  of  these  prisms  are  made  apparent 
with  their  intervening  cementing  substance.  Bruecke  has 
quite  recently  discovered  that  the  sarcous  elements  them- 
selves are  not  elementary  and  simply  solid  bodies,  but 
groups  of  smaller  doubly  refractile  bodies  which  he  calls 
"disdiaclasts"  after  the  phrase  employed  by  Bartholin,  the 
discoverer  of  double  refraction  in  calc  spar.  Immersion  in 
wTater  obliterates  all  traces  of  the  sarcous  elements  and  dissi- 
pates the  appearance  of  striatiou  in  the  muscular  fibre. 


180  THE  GENERAL  PROPERTIES   OF   MUSCLE. 

In  the  present  unsettled  state  of  opinions  upon  the  sub- 
ject, we  shall  continue  to  regard  the  muscular  fibre,  with  its 
enveloping,  nucleated,  sarcolemma,  receiving  the  last  distri- 
bution of  the  vessels  and  nerves,  as  the  ultimate,  anatomical, 
element  of  striped  muscular  tissue.  The  fibre  is  the  cell 
and  the  sarcolemma  is  its  wall.  Krause  has  repeatedly- 
teased  out  muscle  fibre  under  various  reagents  and  found  it 
never  more  than  4  ctm.  (1.6  inch)  in  length. 

Muscle  Protoplasm. 

The  proper  protoplasm  of  muscle,  in  its  living  state,  is 
soft,  even  semi-fluid.  For  some  time  after  removal  from  the 
body  the  fresh  surface  of  a  mass  of  muscle  in  the  butcher's 
stalls  trembles  or  palpitates  under  a  current  of  air.  The 
difiluence  of  muscle  is  seen  to  advantage  in  the  wave-like 
flow  of  its  protoplasm  towards  the  negative  pole  on  the 
application  of  electricity.  So  long  as  it  is  not  excited,  it 
follows  gravity  in  all  directions.  Kuhne  has  seen  a  filaria 
swimming  about  among,  and  winding  in  between,  individual 
sarcous  elements  without  injuring  or  displacing  them,  the 
muscle  protoplasm  closing  in  behind  it,  without  leaving  any 
line  or  trace  of  its  track. 

The  muscle  fibres  collected  into  primary  bundles,  fasciculi, 
and  these  again  into  larger,  secondary  and  tertiary  bundles 
finally  constitute,  en  masse,  as  we  have  seen,  the  individual 
muscle. 

General  Properties  of  Muscle. 

The  muscles  vary  greatly  in  their  shape,  in  their  bulk 
and  in  their  weight.  The  vastus  externus  and  the  glutei 
arc  masses  of  muscular  substance  weighing  pounds;  the 
small  muscles  of  the  middle  ear  weigh  but  a  few  grains. 
There  is  full  as  great  variety  in  their  shape.  Muscles  are 
long  at  the  extremities,  broad  and  flat  in  the  trunk,  short 


THE   NAMES   OF  MUSCLES.  181 

and  thick  about  the  head  and  neck.  The  more  fixed  point 
of  origin  is  called  the  head  or  origin  of  the  muscle,  the  more 
movable  point  of  insertion,  the  tail  or  insertion,  the  ex- 
panded intervening  portion  is  the  body,  the  venter  or  the 
belly. 

Names  of  Muscles. 

Hence  are  the  names  gastrocnemius,  digastricus,  biceps, 
triceps,  etc.,  bellied,  double  bellied,  two  and  three  headed 
muscles,  etc. 

Muscles  are  also  named  according  to  their  uses,  as 
diaphragm,  buccinator,  extensors,  flexors,  adductors,  ab- 
ductors, levators,  depressors,  tensors,  dilators,  etc. ;  or,  ac- 
cording to  their  positions,  as  interspinals,  interossei,  sub- 
clavius,  popliteus,  temporalis,  occipito-frontalis,  etc. ;  or, 
according  to  their  shape,  as  trapezius,  splenitis,  lumbricales, 
scalenus,  deltoid,  gracilis,  etc. ;  according  to  their  dimen- 
sions, as  pectoralis  major  and  minor,  gluteus  maximus, 
medius  and  minimus;  according  to  their  composition,  as 
semi-membranosus,  semi-tendinosus,  complexus,  etc. ;  ac- 
cording to  their  attachments,  as  sterno-cleido-mastoideus, 
genio-hyo-glossus,  etc..  The  gemelli  form  a  pair  of  twins, 
the  sartorius  crosses  the  legs  for  the  sartorial  (tailor's) 
posture,  and  the  risorius  produces  a  smile.  "He  who  re- 
jects with  scorn,"  said  Mr.  Darwin,  "the  belief  that  the 
shape  of  his  own  canines  and  their  occasional  great  develop- 
ment in  other  men,  are  due  to  our  early  progenitors  having 
been  provided  with  these  formidable  weapons  will  probably 
reveal  by  sneering  the  line  of  his  descent.  For,  though  he 
no  longer  intends,  nor  has  the  power,  to  use  these  teeth  as 
weapons,  he  will  unconsciously  retract  his  'snarling  muscles,' 
so  named  by  Sir  Chas.  Bell,  so  as  to  expose  them  ready  for 
action,  like  a.dog  prepared  to  fight." 


182  THE  FORM   AND   SHAPE  OF  MUSCLES. 

Form   and   Shape  of  Muscles. 

Muscles  are  said  to  be  simple,  when  all  the  fibres  are  sim- 
ilar in  direction  in  a  single  body,  as  in  the  sartorius ;  they 
are  compound,  with  one  body  and  several  heads  or  tails,  as  the 
flexors  of  the  fingers  and  toes ;  radiated,  when  spread  out  like  a 
fan  or  a  wheel,  as  the  temporal  and  the  diaphragm  ;  pennated, 
when  arranged  like  the  feathers  upon  a  quill,  as  in  the 
pal  maris  longus ;  hollow,  as  in  the  heart,  the  uterus  and  the 
bladder  (Dunglison). 

Most  curiously  arranged,  finally,  are  those  double  bellied 
muscles,  which  are  caught  at  the  middle  by  an  attachment, 
sometimes  as  by  a  pulley,  and  thrown  off  to  exercise  their 
force  in  a  different  line  from  that  assumed  at  their  origin, 
as  the  digastricus,  and  the  superior  oblique  muscles  of  the 
eyes. 

These  are  mostly  anatomical  points,  it  is  true,  but  are 
mentioned  here  for  the  sake  of  exhibiting  the  individuality 
of  muscles. 

Smooth    Muscle. 

The  construction  and  disposition  of  the  smooth  involun- 
tary muscle  fibre  is  much  more  simple.  It  presents  itself 
in  the  form  of  elongated,  spindle-shaped  cells,  whose  ends 
appear  drawn  out  to  lines  of  extreme  tenuity,  and 
whose  central  nucleus,  rendered  more  apparent  under 
the  action  of  a  strong  acid,  is  a  long  cylindrical  rod 
with  blunt  or  rounded  ends.  Sometimes  the  cell  is 
so  much  reduced  apparently,  by  elongation,  as  to  re- 
semble the  threads  of  filiform  connective  tissue.  This  i3 
the  case  in  the  intestine,  ureters  and  bladder.  On  the 
other  hand,  in  the  trunk  of  the  aorta,  the  smooth  muscle 
cell  is  so  short,  thick,  and  irregular,  as  to  be  with  difficulty 
distinguished  from  epithelial  cells.  It  is  only  by  following 
out  the  vessel  into  its  branches,   where  the  cells  begin  to 


THE   DISPOSITION   OF   SMOOTH   MUSCLE.  183 

elongate,  and  observing  the  transition  forms,  that  the  dis- 
tinction can  be  made.  These  shorter,  thicker,  cells  would 
seem  to  be  a  persistence  of  the  embryonic  stage,  for  at  the 
period  of  original  development  all  the  involuntary  muscle 
cells  present  this  appearance.  I  may  state  here,  parentheti- 
cally, that,  according  to  Lockhardt  Clarke,  muscular  fibre 
can  be  first  distinguished  in  man,  about  the  fourth  or  fifth 
week  of  utero-gestation. 

Disposition   of  Smooth  Muscle. 

Smooth  cells,  arranged  side  by  side,  dovetailing,  at  their 
ends,  with  other  cells,  form  the  layers,  thin  and  single,  or 
thick  and  multiple,  by  superimposition,  which  constitute  an 
essential  feature  in  the  walls  of  the  various  vessels,  tubes, 
bladders,  etc.,  connected  with  the  vegetative  apparatus  of 
the  body.  Thus,  they  form  the  chief  coat  of  the  middle 
sized  arteries,  two  extensive  layers  (the  submucous  and  sub- 
peritoneal) of  the  intestine,  an  important  constituent  in 
the  walls  of  the  bronchial  tubes,  extending  down  to  and  be- 
tween the  pulmonary  alveolae,  the  middle  coat  of  the  gall 
and  urinary  bladders,  renal  pelvis,  ureters,  and  urethra. 
They  occur  in  the  skin,  in  the  form  of  small  rods  or 
bundles  (arrectores  pili)  attached  to  the  hair  bulbs,  and  con- 
nected with  the  oil  and  sweat  glands,  or  in  the  form  of  a 
more  continuous  layer,  as  in  the  tunica  dartos  of  the  scrotum. 
In  the  male  organs  of  generation,  smooth  fibre  is  met  with 
in  the  ducts  in,  and  leading  out  from  the  testicle,  in  the 
large  so-called  glands  (Cowpers  and  the  prostate)  at  the  root 
of  the  penis,  and  forms  an  important  ingredient  in  the  con- 
struction of  the  penis  itself.  In  the  female  organs  of  gener- 
ation, it  is  found  in  the  ovaries,  the  round  and  broad  liga- 
ments, forms  a  coat  in  the  walls  of  the  Fallopian  tubes,  and 
constitutes  the  bulk  of  the  uterus,  which  is  the  largest  mass 
of  it  in  the  body.    Thin  layers  and  fine  bundles  of  smooth 


184  THE  CHEMISTRY   OF   MUSCLE. 

muscular  fibre  are  also  found  in  the  mucous  membranes  (as 
in  the  digestive  tract),  in  the  interior  of  solid  organs  (as  in 
the  calyces  of  the  kidney  and  in  the  spleen).  Finally,  of 
this  tissue  are  formed  the  involuntary  muscles  of  the  eye, 
the  contractors  and  dilators  of  the  pupil,  and  the  (ciliary) 
muscle  of  accommodation.  In  short,  all  visible  contractility, 
independent  of  the  striped  fibres,  is'  due  to  the  presence  in 
the  organ  or  structure  of  this  smooth,  white  and  involuntary 
muscular  tissue. 

The  Chemistry  of  Muscle. 
However  much  the  two  kinds  of  muscular  tissue  may 
differ  in  appearance  or  in  action,  their  chemical  composition 
h  precisely  the  same.  Three-fourths  of  the  substance  of 
muscle  is  water.  Of  the  remaining  fourth,  one-half  is  the 
coagulable  albumenoid  principle  peculiar  to  muscle,  known 
as  myosin.  Myosin  may  be  separated  from  living  muscle 
by  freezing  it,  mincing  it,  and  rubbing  it  up  in  a  mortar 
with  four  times  its  weight  of  snow,  containing  one  per  cent, 
of  common  salt  (Kiihne).  The  resulting  mixture,  the 
muscle  plasma,  as  it  is  called,  soon  gelatinises  to  a  firm 
mass,  which  afterwards  separates  into  a  clot  and  surround- 
ing fluid.  The  clot  is  myosin ;  the  fluid,  muscle  serum. 
As  the  products  of  metamorphosis,  there  are  found  in 
muscle  numerous  extractive  matters,  as  creatine,  xanthin, 
hypoxanthin,  sarcosin,  inosite,  and  traces  of  uric  acid, 
though  "urea  is  conspicuous  by  its  absence."  Nearly  80 
per  cent,  of  the  ash  of  muscle  is  composed  of  the  salts  of 
potash  and  phosphorus. 

The  Reaction  of  Muscle. 

The  reaction  of  fresh  muscle,  at  rest,  is  neutral  or  faintly 
alkaline,  but  during  and  after  contraction  it  is  acid.  The 
peculiar  form  of  lactic  acid  found  in  muscle  is  directly  gen- 
erated by  the  oxidation  of  the  carbo-hydrates  of  the  blood, 


THE  SPECIFIC  PROPERTIES  OF  MUSCLE.  185 

and  when  small  in  quantity,  as  during  rest  of  the  muscle, 
is  neutralised  by  the  alkalinity  of  the  blood  ;  but  when  its 
quantity  is  much  increased,  as  during  the  rapid  oxidation 
attending  contraction,  it  cannot  be  sufficiently  neutralized 
at  once,  and  accumulates  to  render  the  muscle  acid  for  a 
time.  So  the  free  access  of  oxygen  soon  renders  acid  a 
freshly  dissected  muscle,  separated  from  the  body.  The 
accumulation  of  acid  in  the  muscle  marks  the  stage  of 
weariness  or  fatigue.  Ranke  found  that  a  frog's  muscle 
which  had  become  powerless  from  fatigue  was  speedily  re- 
stored to  activity  after  the  injection  (from  the  heart)  of 
very  weak  solutions  of  carbonate  of  soda,  which  carried  off 
the  acid  by  presenting  it  a  base.  Fresh  and  active  muscle 
is  speedily  rendered  powerless  by  the  injection  into  its 
vessels  of  even  highly  diluted  lactic  acid. 

Specific   Properties  of  Muscle. 

The  muscular  is  said  to  be  one  of  the  master  tissues  of  the 
body,  and  whether  we  regard  the  nature  or  the  mere  num- 
ber of  the  properties  wrth  which  it  is  endowed,  there 
appears  to  be  justification  for  assigning  it  to  this  dominant 
place.  For  muscle  has  the  passive  property  of  elasticity ; 
that  kind  of  constant,  effortless,  insensible,  contraction  known 
as  tonicity;  a  peculiar  sensibility ;  and,  higher  than  all  these, 
a  characteristic  contractility,  which  makes  itself  manifest  in, 
and  is,  in  part,  the  immediate  cause  of  nearly  all  the  phe- 
nomena of  animal  life.  In  addition  to  all  these  properties, 
muscle  generates  heat  and  electricity,  and  in  its  action  pro- 
duces sound,  which  is,  however,  an  effect  rather  than  property. 

The  Elasticity   of  Muscle. 
Elasticity  is  a  property  possessed  by  muscular  tissue  in 
high  degree.    The  semi-fluid  muscle   protoplasm,  is  itself 
somewhat  elastic  or  resilient,  and  the  sarcolemma,  the  in- 
vesting sheet  of  connective  tissue,  is  highly  elastic.     It  is 

16 


186  THE  ELASTICITY  OF  MUSCLE. 

the  extensibility  and  elasticity  of  muscles  at  rest  which  per- 
mit the  bones  to  be  moved  in  different  directions  by  antago- 
nistic muscles,  and  it  is  to  the  property  of  elasticity  alone, 
or  in  great  part,  that  is  due  the  restoration  of,  so  to  speak, 
displaced  members  to  their  former  place.  The  purely 
passive  property  of  elasticity  thus  greatly  economises  active 
muscular  force.  It  is  always  ready,  requires  no  innerva- 
tion, and  manifests  its  action  at  once.  It  permits  the  walls 
of  hollow  organs,  like  the  stomach,  the  bladder,  and  the 
uterus,  to  be  more  or  less  distended,  reacting  all  the  time 
upon  their  contents,  to  assist  the  active  property  of  muscle 
in  securing  their  extrusion.  The  auricles  of  the  heart,  for 
instance,  are  passively  distended  or  dilated  with  the  ease  of 
a  soap  bubble,  by  the  influx  of  blood,  and  are  emptied 
almost  entirely  without  the  intervention  of  active  muscular 
force.  The  degree  of  elasticity  is  different,  of  course,  in 
different  muscles,  being  dependent  upon  the  size  of  the 
muscle  and  the  quantity  of  accessory  structure  (connective 
and  elastic  tissue)  it  may  contain.  But  the  elasticity  of 
muscle  far  surpasses  that  of  most  other  elastic  bodies.  A 
bundle  of  silk  threads  or  of  metal  wires  will  not  suffer  the 
same  extension  without  rupture.  Muscle  resembles  more 
closely  a  bundle  of  threads  of  caoutchouc  or  India  rubber. 
The  specific  elasticity  of  a  substance  is  determined  by  the 
weight  or  force  required  to  extend  it  within  the  limits  of 
perfect  restoration.  If  Ave  compare,  thus,  different  substances 
with  muscle,  it  is  found  that  the  weight  required  to  extend 
the  one-thousandth  of  its  length,  a  rod  or  thread  of  one 
square  millimeter  diameter  would  be  as  follows : 

Grammes.     Grains. 
Steel,        -         -         -         17278000  (1151866) 
Copper,  -         -         -    10519000   (701266) 

Pine  wood,        -        -  1113000      (74200) 

Frog's  Muscle,       -         -  273  (18) 


THE  TON/CITY  OF  MUSCLE.  187 

These  figures  represent  the  co-efficient  of  elasticity  of   the 
different  substances. 

Of  course,  there  are  limits  to  the  elasticity  of  muscle. 
Thus  Marey  found  that  the  detached  gastrocnemius  muscle 
of  the  frog  could  be  extended  with  a  weight  of  300  grains 
to  the  degree  of  the  one-fiftieth  of  an  inch  with  perfect  re- 
covery after  removal  of  the  weight,  while  a  weight  of  750 
grains  completely  disabled  its  elasticity.  Moreover,  rapidly 
repeated  subjection  to  experimentation  diminishes  and 
finally  exhausts  the  elasticity  of  muscle,  inducing  the  re- 
laxed and  flabby  state,  characteristic  of  fatigue. 

Tonicity  of  Muscle. 

Tonicity  has  been  described  as  insensible  contraction  of 
muscle,  inherent  in  the  muscle  protoplasm  itself,  and  inde- 
pendent of  the  nervous  system.  It  was  said  to  manifest 
itself  in  the  retraction  of  muscle  cut  across  (gaping  of 
wounds),  and  in  the  distortion  of  the  paralysed  side  of  the 
face  in  facial  hemiplegia  from  traction  by  the  sound  side. 
But  recent  experiments  have  clearly  demonstrated  that 
both  these  phenomena  are  due  to  elasticity.  The  muscles 
are  always  somewhat  stretched  beyond  their  normal  length, 
so  that  retraction  of  divided  surfaces  is  a  natural  result  of 
section.  Both  time  and  force  are  thus  economised  by  this 
elongation  and  elasticity  of  muscular  fibre.  Muscles 
stretched  by  the  contraction  of  opposing  muscles  fairly 
spring  back  to  their  former  position  without  effort  or  loss  of 
time.  When  a  muscle  is  separated  from  its  attachments  it 
shrinks  upon  itself,  and  the  muscular  tubes  (fibres)  are  seen, 
under  the  microscope,  not  to  lie  in  straight,  but  in  wavy  or 
zig-zag  lines.  It  is  the  advantage  taken  by  the  persisting 
elasticity  upon  the  sound  side,  of  the  impaired  elasticity  on 
the  affected  side,  that  produces  the  distortion  of  the  face  in 
facial  palsy. 


188  TONICITY,   A   REFLEX   PHENOMENON. 

Nevertheless,  there  is  an  insensible  and  involuntary  con- 
traction (tonicity)  of  all  the  muscles,  both  voluntary  and 
involuntary,  which  manifests  itself  in  the  muscles  of  the 
skeleton  as  well  as  in  the  smooth  fibre,  where  it  secures  a 
certain  tonicity  of  the  vessel  walls,  of  the  sphincters,  etc. 

Tonicity,    a    Reflex   Phenomenon. 

But  this  tonicity  is  by  no  means  an  independent  property 
in  the  muscular  tissue.  It  is  derived  entirely  from  the 
nervous  system,  and  is  a  purely  reflex  phenomenon.  Up  to 
even  a  short  time  ago,  this  influence  of  the  nervous  system 
upon  the  muscles,  was  regarded  as  an  automatic,  an  original 
or  spontaneous  action,  developed  in  the  spinal  cord.  It  is 
now  known,  however,  that  this  action  is  excited  by  outside 
(peripheral)  influences,  and  is  conducted  through  sensitive 
nerves  (from  the  skin,  etc.)  to  the  cord,  whence  it  is  trans- 
ferred through  motor  nerves  to  the  muscles.  For  it  has 
been  shown  by  Brondgeest  that  section  of  the  sciatic  plexus 
of  nerves  on  one  side  in  the  frog,  after  division  of  the  spinal 
cord  below  the  medulla  oblongata,  destroys  the  tonicity  of 
the  muscles  upon  the  operated  side,  while  it  is  left  intact 
upon  the  sound  side.  When  a  frog  thus  operated  upon  is 
suspended,  all  the  joints  upon  the  operated  side  hang  loose 
and  flabby,  while  those  on  the  sound  side  still  retain  their 
natural  degree  of  flexion.  Liegeois  cut  the  sciatic  nerve  in 
the  frog  upon  one  side  only,  and  then  divided  the  gastroc- 
nemius muscle  upon  both  sides,  when  it  was  observed  that 
the  retraction  (gaping)  was  much  less  marked  upon  the 
ope  rated  side. 

That  this  influence  from  the  nervous  system  is  entirely 
reflex  is  proven  by  the  fact  that  section  of  the  posterior  (sen- 
sitive) roots  of  the  nerves  has  the  same  effect  as  section  of  the 
entire  nerves.  Moreover,  after  section  of  the  posterior 
nerve  roots,   a  stronger  irritant  must  be    applied  to   the 


THE  TONICITY  OF  INVOLUNTARY  MUSCLE.  189 

anterior  roots  to  produce  the  same  convulsive  movement 
in  the  muscles,  proof  that  additional  artificial,  is  required  to 
substitute  the  lacking  natural,  stimulus. 

Tonicity  of    Involuntary   Muscle. 

A  continuous,  though  feeble,  discharge  of  nerve  force  is 
also  received  by  the  involuntary  muscles  securing  to  them 
a  constant  tonicity.  After  section  of  the  nerves  distributed 
to  their  walls,  the  vessels  dilate,  and  that  this  influence  also 
comes  from  the  cord  is  proven  by  the  observation  that 
spinal  hemiplegias  are  attended  with  paralysis  of  the  arteries 
only  upon  one  side.  Here  again,  however,  we  have  to  deal 
with  reflex  and  not  automatic  processes,  for  Goltz  has  dem- 
onstrated that  vessel  tonicity  may  be  affected  (increased) 
by  irritation  of  distant  sensitive  nerves  or  surfaces,  as  from 
the  intestines,  or  paralysed  by  their  destruction.  So 
strychnia  will  continue  to  cause  contraction  of  arteries 
below  the  line  of  section  oil  the  spinal  cord. 

The  sphincters  are  held  in  a  state  of  continuous  contrac- 
tion in  the  same  way.  Giannuzi  and  Nawrocki  found  that 
more  force  had  to  be  used  to  overcome  sphincteric  contrac- 
tion (by  the  injection  of  water)  when  the  nerves  were  intact 
than  after  their  division.  Heidenham  and  Colberg  had 
already  demonstrated  this  fact  with  regard  to  the  bladder 
They  introduced  water  of  the  temperature  of  the  body  into 
the  interior  of  the  bladder  of  a  rabbit,  and  observed,  by 
means  of  a  manometer,  that  it  required  a  pressure  of  27 
centimetres  to  overcome  the  tonicity  of  the  sphincter  and 
permit  escape  of  the  water.  They  now  killed  the  animal  to 
annul  all  innervation,  and  found  that  the  water  escaped  at 
a  pressure  of  5  centimetres.  In  the  dog  a  higher  pressure 
was  required  in  both  cases,  but  the  result  was  the  same. 
It  is  probable  that  the  remote  exciting  agencies  producing 
the  tonicity  of  the  sphincters,   the  bladder,   the   dilator 


190  THE  SENSIBILITY   OF  MUSCLE. 

pupillae,  etc.,  are  the  nutritive  changes  in  constant  opera- 
tion about  the  peripheral  distribution  of  the  nerves,  as  well 
as  in  the  nerve  centres  themselves. 

The  tonus  of  muscle,  therefore,  is  no  proof  of  the  spon- 
taneous generation  or  automatism  of  force.  Closer  investi- 
gation always  dissipates  such  conceptions  and  it  is  probable 
that  this  term  will  in  a  few  years  be  entirely  discarded  from 
physiology,  will  be  shelved  away  along  with  other  "vital 
forces,"  with  the  autochthonous  (spontaneous)  or  idiopathic 
genesis  of  disease,  and  other  mysteries  of  medicine. 

The  Sensibility  of  Muscle. 

Sensibility  is  that  peculiar  property  which  enables  us  to 
estimate  the  amount  of  effort  necessary  to  execute  different 
movements,  to  overcome  resistance  or  to  appreciate  different 
weights.  It  is  some  times  described  fes  a  sixth  special  sense, 
oftener  as  a  general  sense,  and  occasionally  as  a  kind  of 
transition  sense  between  the  two.  Those  who  deny  its 
independent  existence  regard  it  as  a  peculiar  modification 
of  the  sense  of  touch.  In  fact  three  theories  have  been 
propounded  to  account  for  the  muscular  sense:  1,  that 
there  are  no  special  sensitive  nerve  fibres  distributed  to 
muscles.  We  are  cognisant  only  in  a  general  way  of  the 
amount  of  nerve  force  sent  to  a  muscle  though  its  motor 
nerves.  We  recognise  the  intention  of  muscular  movement 
but  not  its  execution  (Wundt) :  2,  We  are  informed  of  the 
contraction  of  muscle  only  by  the  sensations  produced  in 
the  skin  or  mucous  membrane  covering  them,  that  is,  through 
the  tactile  sense  (Auber) ;  3,  Centripetal  (sensitive)  nerve 
fibres  pass  from  the  muscles  to  the  nerve  centres  (Arnold, 
Brown-Sequard,  etc.). 

Sensibility  and  Sensation  of  Touch. 

That  the  muscular,  is  entirely  independent  of  the  tactile, 
sense,  was  demonstrated  some  time  ago  by  Claude  Bernard 


SENSIBILITY  AND  SENSATION  OF  TOUCH.  191 

who  found  that  removal  of  the  skin  (decortication)  did  not  at 
all  affect  the  sensibility  of  the  subjacent  muscles.  Complete 
insensitiveness  of  the  skin  was  also  produced  by  division  of 
all  the  cutaneous  nerves,  but  the  muscular  sense  still  remained 
intact,  as  the  animal  thus  operated  upon  continued  to  be 
able  to  walk,  etc.  If,  however,  the  posterior  (sensitive)  nerve 
roots  were  cut,  the  muscular  sense  was  very  greatly  impaired 
or  entirely  destroyed.  Moreover,  the  muscular  sense  is 
much  finer  than  the  tactile  sense;  it  will  appreciate  lighter 
shades  of  difference.  The  feelings  of  weariness  or  fatigue 
which  supervene  after  violent  or  long  continued  exercise, 
the  positive  pain  experienced  in  the  cramp  of  tetanus,  the 
spasm  of  convulsion,  or  even  the  exaggerated  physiological 
action  of  the  uterus  (labor),  or  heart  (palpitation),  are  patho- 
logical and  physiological  proofsof  a  muscular  sense  dependent 
upon  the  existence  of  sensitive  nerves.  In  truth,  C.  Sachs 
found,  after  division  of  all  the  anterior  (motor)  nerve  roots, 
some  undegenerated  nerve  fibres  in  the  sartorius  muscle  of 
the  frog  which  could,  of  course,  belong  only  to  the  posterior 
(sensitive)  roots.  Terminations  of  sensitive  nerve  fibres, 
corpuscles  of  Pacini,  had  long  before  been  discovered  in 
quantity  in  the  perimysium,  and  about  the  joints,  at  the 
points  of  insertion  of  the  tendons,  whose  function  in  all 
probability  is  to  receive  and  transmit  the  muscular  sense. 
Lastly,  the  tactile  sense  may  be  entirely  paralysed,  while 
the  muscular  sense  remains  intact,  or  vice  versa.  Thus 
in  locomotor  ataxia,  the  tactile  sense  may  be  little  or  not  at 
all  affected,  while  the  muscular  sense  is  so  much  impaired 
as  to  require  the  aid  of  visual  sense  in  walking.  "We  lean 
upon  our  eye-sight  in  walking,"  said  Mr.  Mayo,  "as  upon 
crutches."  An  individual  thus  affected  falls  when  he  closes 
his  eyes.  Duchenne  has  put  upon  record  the  curious  case 
of  a  nurse,  who  had  lost  the  muscular  sense  in  one  of  her 
arms,  and  who  could  only  carry  a  child  by  constantly  watch- 


192  THE  SENSATION  OF  FATIGUE. 

ing  that  arm ;  as  soon  as  she  turned  her  eyes  away  from  it, 
the  limb  would  fall  helpless  to  her  side.  But  in  this  case 
the  cutaneous  sense  was  not  affected.  On  the  other  hand, 
there  are  certain  diseases  of  the  spinal  cord  in  which  the  sense 
of  touch  or  pressure  in  the  skin  is  entirely  annulled,  while 
it  persists  intact  in  the  subjacent  muscles.  Thus,  the  case 
is  reported  by  Eigenbrodt  of  a  patient  who  could  distinguish, 
by  the  effort  of  lifting,  the  difference  between  thirty  and 
thirty-two  pounds,  but  could  not  feel  a  five  pound  weight 
resting  upon  his  passive  hand. 

Of  the  ordinary  sense  of  touch,  muscle  possesses  little  or 
none.  The  pain  experienced  in  amputations,  belongs  to  the 
section  of  the  skin,  and  is  scarcely  perceived  in  the  division 
of  the  muscle  or  bone.  Muscle  may  be  cut,  pinched,  burned, 
subjected  to  all  kinds  of  irritation,  without  exciting  much, 
if  any,  pain.  It  is  believed  that  even  the  intense  pains  of 
cramps  are  due  simply  to  the  violent  traction  upon  the 
points  of  origin  and  insertion  of  the  muscle.  The  involun- 
tary muscles  are  equally  devoid  of  the  sense  of  touch  or 
pain.  Haller  could  never  excite  pain  in  his  experiments 
upon  the  heart,  and  Harvey  found  that  he  could  manipulate 
it  freely  in  a  case  of  its  exposure  after  caries  of  the  sternum 
without  producing  the  least  sensation.  Bichat  made  the 
same  observation  upon  the  bladder,  and  every  gynaecologist 
is  aware  of  the  insensibility  of  the  uterus,  whose  cervix  is 
burned,  scraped  and  even  split,  almost  without  consciousness 
on  the  part  of  the  patient. 

The  Sensation  of  Fatigue* 

But  the  muscles  are  extremely  sensitive  to  the  peculiar 
pain  of  muscular  fatigue,  which  continues  to  be  felt  long 
after  its  cause  has  been  relieved.  Weber  has  shown  that 
the  fatigue  of  muscle  is  due  to  chemical  change  in  the 
muscle  substance,  to  the  consumption  of  oxygen  (Petten- 


THE  EXERCISE  OF  THE  MUSCULAR  SENSE.  193 

kofer  and  Yoit)  and  to  the  accumulation  of  the  products  of 
oxidation  (carbonic  acid,  lactic  acid,  acid  phosphate  of  lime, 
etc. — Hanke).  We  can  thus  understand  how  it  was  that 
Bichat  could  produce  violent  pain  in  muscle  by  injecting 
into  the  arteries  of  living  animals  irritating  fluids,  like  ink, 
dilute  acids,  and  wine.  The  fatigue  of  muscle  must  continue 
until  the  blood  shall  have  had  time  to  decompose  or  con- 
duct away  the  irritating  matter.  Hence,  the  efficacy  of 
hot  baths  and  massage  (friction),  which  by  accelerating  the 
capillary  circulation,  more  quickly  dissipates  the  products 
of  muscular  action  (products  of  combustion). 

The  rapid  accumulation  of  these  products  of  decomposi- 
tion in  fever,  which  is,  in  essence,  a  too  rapid  oxidation, 
accounts  for  the  deep  seated  muscular  pains  (as  in  "break 
bone  fever,"  lumbago  of  the  exanthemata  (small  pox),  etc.) 
attending  this  condition. 

The  Exercise  of  the  Muscular  Sense. 

The  muscular  sense  is  thus  quite  distinct  from  every 
other  sense.  It  acquaints  us  unconsciously  with  the  position 
and  relations  to  each  other  of  the  various  parts  of  the  body 
and  informs  us  of  the  position  and  properties  of  external 
bodies.  It  enables  us  to  appreciate  differences  beyond  the 
range  of  other  senses.  Thus  it  is  finer  than  the  sense  of  touch. 
It  will  correctly  discriminate  between  weights  which  stand 
to  each  other  in  the  relation  of  thirty-nine  and  forty, 
provided  the  weights  are  not  too  light  or  too  heavy  (Weber). 
Increase  is  easier  detected  than  decrease  (Panum  and  Dohrn). 
It  estimates  with  the  finest  nicety  the  degree  of  contraction 
to  be  excited  in  a  muscle,  or  group  of  muscles,  for  the 
execution  of  a  given  purpose,  and  makes  us  cognisant  of  the 
exact  degree  of  contraction  and  relaxation  existing  during 
the  execution  of  the  movement.  The  muscular  sense  thus 
establishes  the  harmonious  and  coordinate  action  of  the 

17 


194  THE  EXERCISE  OF  THE  MUSCULAR  SENSE. 

different  muscles  in  all  the  voluntary  and  involuntary 
acts  of  the  body,  in  assuming  and  maintaining  its 
different  positions,  as  in  standing,  walking,  balancing, 
dancing,  riding,  swimming,  etc. ;  in  executing  the  finer 
movements  of  the  handicrafts,  playing  upon  musical  in- 
struments, etc. ;  in  arranging  the  features  and  changing  the 
expression  of  the  face  and  members  in  the  infinite  variety 
of  gesticulation ;  in  the  quick  movements  of  the  eye,  and, 
finest  and  nicest  of  all,  in  the  delicate  modulations  of  voice 
and  speech. 

So  it  was  no  wonder  that  Sir  Chas.  Bell,  the  eloquent 
English  anatomist,  could  not  restrain  himself  after  observ- 
ing the  fineness  and  nicety  of  the  action  of  the  muscular 
sense,  from  expressing  his  admiration  in  a  fitting  tribute  of 
praise.  "When,"  he  exclaims,  "a  blind  man  or  a  man 
blindfolded,  stands  upright,  neither  leaning  upon  or  touch- 
ing aught,  by  what  means  does  he  maintain  his  erect  position  ? 
The  symmetry  of  his  body  is  not  the  cause.  A  statue 
of  the  finest  proportion  must  be  soldered  to  its  pedestal,  or 
the  wind  will  cast  it  down.  How  is  it,  then,  that  a  man 
sustains  the  perpendicular  posture  or  inclines  in  the  due 
degree  towards  the  wind  that  blows  upon  him?  It  is 
obvious  that  he  has  a  sense  by  which  he  knows  the  inclina- 
tion of  his  body ;  and  that  he  has  a  ready  aptitude  to  adjust 
the  parts  of  it  so  as  to  correct  any  deviation  from  the  per- 
pendicular. What  sense  is  this?  He  touches  nothing,  sees 
nothing;  it  can  only  be  by  the  adjustment  of  the  muscles 
that  the  limbs  are  stiffened,  the  body  firmly  balanced  and 
kept  erect.  In  truth,  we  stand  by  so  fine  an  exercise  of  this 
power,  and  the  muscles,  from  habit,  are  directed  with  so 
much  precision  and  with  an  effort  so  slight,  that  we  do  not 
know  how  we  stand." 

Such  is  what  is  meant   by  the   muscular    sense.      The 
Germans,  very  appropriately  call  it  the  "  Gemein-gefuhl" 


MUSCLE  AND  ITS  PROPERTIES.  195 

the  general  or  common  feeling  of  the  body.  The  vigor  of 
this  sense  is  a  criterion  of  health ;  it  was  the  euphora  of  the 
ancients,  the  easy  carriage  and  light  weight  of  the  body. 
The  muscular  sense  is  the  physical  conscience.  The  indi- 
vidual who  has  this  conscience  or  consciousness  sound, 
enjoys  a  luxury  in  mere  existence. 


LECTURE    X. 
MUSCLE  AND  ITS  PROPERTIES. 

C  ONTENTS. 

Contractility  of  Muscle — Effects  of  Muscular  Contraction — Degree  of 
Contraction — Change  of  Form — Agents  which  Induce  Contraction — 
Direct  and  Indirect  Excitation — Thermal  Excitation — Electric  Excita- 
tion— The  History  of  Galvanism — The  Action  of  Induced  Electricity 
— The  Action  of  Nerve  Force — The  Sound  of  Muscle  Contraction — 
The  Muscular  "Wave — Independence  of  Muscular  Force — The  Action 
of  the  Sulphocyanide  of  Potassium  and  Curare — The  Generation  of 
Heat — The  Generation  of  Electricity — Du  Bois-Reymond's  Theory 
of  Muscular  Action — Rigor  Mortis — Post-Mortem  Changes  in  Muscle 
—The  Fuel  of  Muscle — The  Oxygen  Supply — The  Dependence  of 
-MTTscle  upon  Blood — The  Muscles  as  Levers — The  Absolute  Power 
of  Muscle — The  Power  of  Muscle  in  General — Differences  of  the 
Sexes — Differences  in  Different  Animals — The  Velocity  and  Delicacy 
of  Muscular  Action. 

We  have  to-day  to  conclude  the  study  of  muscle  with  the 

consideration  of    its  remaining    properties,  the    chief    of 

which  is 

Contractility. 

"We  observe  then,  first,  that  the  mode  of  con  traction  is  very 
different  in  the  two  kinds  of  muscular  tissue.  Striated 
muscle  responds  to  an  irritant  almost  suddenly,  always 
forcibly,  and  as  quickly  returns  to  its  former  state.  Smooth 
muscle  responds  slowly,  always  comparatively  feebly,  and 
as  slowly  returns  to  its  former  state.    The  slow,  undulatory, 


196  THE   CONTRACTILITY   OF   MUSCLE. 

so-called  peristaltic,  action  of  the  smooth  muscle  of  the 
intestinal  walls,  manifest  upon  laying  open  the  abdominal 
cavity  of  an  animal,  best  exhibits  the  mode  of  contraction 
of  smooth  muscle  fibre.  The  intestines,  at  first  motionless, 
soon  exhibit  feeble  contraction,  which  gradually  increases 
to  vermicular  motion,  until  the  whole  canal  "writhes  like  a 
mass  of  earth  worms,"  to  gradually  become  again  quies- 
cent. The  uterus  in  labor  typically  exemplifies  the  action 
of  involuntary  muscle.  If  the  hand  be  placed  upon  the 
abdomen  at  the  commencement  of  a  pain,  the  uterus  is  felt  to 
"gather  up"  its  fibres,  to  become  gradually  indurated,  and 
then  slowly  to  relax  to  the  condition  in  the  intervals 
between  pains.'  The  character  of  the  pain  itself,  a  gradual 
increment  to  an  acme,  and  then  a  gradual  decrement  to 
more  or  less  complete  relief,  exhibits  the  absence  of  any 
sudden  force. 

But  there  is  a  difference  in  the  quickness  or  sluggishness 
of  response  in  different  involuntary  muscles.  Thus  the 
muscles  within  the  eyeball,  i.  e.,  the  muscles  of  the  iris 
and  the  tensors  of  the  choroid  (muscles  of  accommodation), 
respond  very  nearly  as  promptly  as  voluntary  muscles ; 
next  in  order  of  promptness  rank  the  muscular  wTalls 7)Tthe 
intestines  and  ureters,  and  slowest  of  all,  is  that  of  the 
bloodvessels,  especially  of  the  arteries,  which,  however, 
compensate  for  it  in  some  degree  by  the  long  persistence  of 
contraction. 

Legros  and  Onimus  concluded  from  their  observations, 
that  smooth  muscle  was  influenced  more  by  direct  excitation 
of  its  substance  than  by  excitation  of  the  nerves,  and  that 
the  disuse,  which  would  reduce  striped  muscle  to  an  inactive 
mass  of  fat,  had  little  or  no  effect  upon  the  anatomical 
or  physiological  integrity  of  smooth  muscle. 

The  voluntary  muscle  fibres  reach  the  bones  only  by  the 
intervention  of    membranes  and  tendons.     Each  fibre  is 


THE  EFFECT  OF  MUSCULAR  CONTRACTION.  197 

reduced  at  its  end  to  a  point,  with  flat,  facetted,  sides,  like  a 
diamond  or  a  sharpened  lead-pencil,  and  is  thus  embraced  by 
the  connective  tissue  structure  of  the  tendon.  The  tendon 
is  the  conductor  of  force.  It  plays  the  part  of  the  line 
which  connects  the  horse  to  the  canal-boat. 

Effect  of  Muscular  Contraction. 

Shortening  is  only  another  name  for  contraction.  In 
contracting,  muscle  shortens,  and,  in  the  case  of  long  muscles, 
approximates  the  connected  bones.  Muscles  in  the  form  of 
tubes  (canals,  vessels,  etc.)  diminish,  in  shortening,  the  caliber 
of  the  tube  or  obliterate  it  altogether.  It  is  the  spasmodic 
contraction  of  the  cerebral  vessels,  which  induces  the  pro- 
found anaemia  of  the  brain  and  pallor  of  the  face  as  the 
immediate  cause  of  epilepsy.  And  it  is  this  exercise  of 
contractility  in  lesser  degree  which  regulates  the  blood 
supply  to  individual  organs  independently  of  the  action 
of  the  heart.  The  bloodvessels  become,  thus,  local  hearts,  at 
the  portals,  and  in  the  substance,  of  each  organ  and  structure 
to  increase  or  diminish  the  supply  of  blood  according  to  the 
demand.  Something  of  this  local  increase  and  decrease  is 
observable  in  the  face  under  the  action  of  the  emotions. 
The  face  is  suffused  with  blood  under  the  excitement  of 
modesty  or  shame  and  is  blanched  under  anxiety  or  fear. 
Thus,  Donne  says: — 

"The  eloquent  blood 
Spoke  in  her  cheeks,  and  so  distinctly  wrought, 
You  might  have  almost  said  her  body  thought." 

And  Petrarch  descants  upon 

"Quel  vago  impallidir." 
(That  charming  pallor.) 

A  vaulted  muscle  has  its  arch  reduced  by  contraction, 
brought  nearer  to  a  plane  surface,  and  thus,  in  the  case  of 
the  diaphragm,  is  the  vertical  capacity  of  the  chest  increased 


198  THE  DEGREE  OF  CONTRACTION. 

and  inspiration  effected.  Ring  muscles,  like  the  sphincters 
and  orbiculars,  in  contracting,  "purse  up"  their  respective 
orifices,  and  hollow  muscles  obliterate  their  cavities  to 
entirely  empty  themselves  of  contents. 

Degree  of  Contraction. 

But  it  is  only  in  extreme  cases  of  cramp,  as  in  tetanus,  or 
in  extraordinary  effort,  that  a  muscle  attains  its  utmost 
degree  of  contraction.  The  bones  very  greatly  limit  the 
contraction  of  the  long  muscles.  Thus  the  biceps  will 
contract,  when  detached,  nearly  five-sixths  of  its  length, 
but,  attached,  its  shortening  is  limited  to  but  one  to  two- 
sixths.  In  tetanus  it  may  reach  three-fifths.  Strange  to 
say,  it  is  no  matter  how  much  muscles  vary  in  size  or  bulk, 
the  per  cent,  shortening  remains  about  the  same.  Some 
muscles  (the  glutei)  weigh  pounds,  or  measure  feet  in 
length  (the  sartorii),  and  others,  the  muscles  of  the  middle 
ear,  but  a  few  grains,  and  measure  but  a  few  lines,  but  the 
proportionate  shortening  remains  about  the  same. 

Change  of  Form. 

The  loss  which  a  contracted  muscle  has  experienced  in 
length  is  in  very  nearly  exact  correspondence  to  its  gain  in 
breadth.  We  may  feel  the  muscles  (biceps)  in  action  swell. 
It  was  formerly  believed  that  muscle  absolutely  gained  in 
bulk,  but  the  ingenious  experiments  of  the  older  physiolo- 
gists entirely  disproved  this  belief.  Thus  Sir  Gilbert  Blane 
inserted  a  glass  tube  into  the  perforated  cork  of  a  glass  jar 
and  filled  the  jar  with  water  up  to  a  certain  level  in  the  tube. 
He  now  introduced  a  living  eel  into  the  jar  and  irritated  it 
t  by  means  of  a  stick,  also  inserted  through  the  cork,  to 
active  contractions.  Though  the  slightest  increase  in  the 
bulk  of  the  animal  would  have  been  registered  in  the  tube 
by  an  elevation  in  the  column  of  water,  no  such  change  in 


AGENTS  WHICH   INDUCE   CONTRACTION.  199 

its  level  could  be  observed.  Barzellotti  made  the  same 
experiment  with  a  frog,  inducing  contractions  in  the  half 
of  its  body,  which  had  been  introduced  into  the  jar,  by  means 
of  galvanism,  with  the  same  result.  The  truth  is,  muscle 
rather  diminishes  than  increases  in  bulk  during  contraction. 
Erman  was  able  to  make  this  observation  by  repeating 
the  experiment  of  Blaine  and  taking  the  precaution  to 
graduate  the  glass  tube  to  great  nicety.  Valentin  appended 
a  weight  to  a  marmot's  muscle,  suspended  in  a  jar  filled 
with  dilute  albumen,  so  that-  its  specific  gravity  could  be 
accurately  weighed  upon  delicate  scales,  and  observed  that 
the  muscle  in  contracting,  displaced  less  water  than  before. 
He  thus  found  that  while  the  specific  gravity  of  the  muscle 
increased  from  1061  to  1062,  its  loss  in  volume  amounted  to 
T3To  °f  ^s  whole  mass,  a  diminution  so  slight  as  to  be 
generally  unconsidered.  Practically,  a  muscle  gains  in 
thickness  what  it  loses  in  length.  If  a  lever  be  laid  upon  a 
muscle  placed  horizontally,  "the  thickening  of  the  muscle 
will  raise  up  the  lever,  and  cause  it  to  describe  on  a  record- 
ing surface  a  curve  exactly  like  that  described  by  a  lever 
attached  to  the  end  of  the  muscle"  (Foster). 

Agents  which  Induce  Contrction. 

The  agents  which  may  induce  contraction  in  muscle  are 
very  various.  Any  mechanical  force  (a  blow,  a  prick),  any 
chemical  irritant  (cholic  acid),  sudden  change  of  tempera- 
ture, the  various  forms  of  electricity,  may  evoke  fibrillar 
twitchings  or  mass  motion.  But  in  the  body,  muscle 
contracts  only  in  obedience  to  nervous  influence.  In  other 
words,  muscle  tissue  is  something  like  the  machinery  of  an 
engine.  It  has  the  capacity  for  work,  but  can  not  work  of 
itself ;  it  must  first  be  stimulated  by  extraneous  forces, 
that  is,  muscle  is  machinery  for  the  transformation  of  some 
other  force  into  muscular  force. 


200  DIRECT  AND  INDIRECT  EXCITATION. 

Direct  and  Indirect  Excitation. 

The  outside  force  may  act  upon  the  muscle  directly,  or 
it  may  act  upon  the  muscle  through  the  intervention  of  the 
nerves.  As  a  rule,  the  agents  which  superinduce  direct 
muscular  contraction  will  also  effect  it  indirectly.  Iviihne, 
who  has  made  an  exhaustive  study  of  this  subject,  states  that 
there  are  some  substances  which  easily  cause  contraction  of 
muscles  when  applied  to  them,  even  if  greatly  diluted; 
whereas,  to  produce  the  same  effect  through  the  nerves,  they 
require  to  be  concentrated.  Among  these,  are  the  mineral 
acids,  especially  muriatic  and  nitric  acids ;  the  basic  salts, 
as  chloride  of  sodium,  chloride  of  potassium,  chloride  of 
lime  ;  as  well  as  some  organic  substances,  as  acetic  acid, 
lactic  acid  and  glycerine.  A  second  class  of  substances 
induce  contraction  equally  whether  applied  to  the  nerve  or 
to  the  muscle.  Among  these  are  caustic  potash  or  soda.  A 
third  class  of  chemical  substances  act  powerfully  on  the 
muscle,  but  not  at  all  upon  the  nerve ;  such  as  chromic  acid, 
sulphate  of  copper,  chloride  of  iron,  basic  and  neutral  acetate 
of  lead,  lime  and,  above  all,  ammonia.  A  fourth  class  of 
substances  act  exactly  in  an  opposite  manner,  that  is,  upon 
the  nerve,  but  not  on  the  muscle,  or  very  slightly  so  ;  such 
as  creosote,  alcohol,  concentrated  glycerine  and  undiluted 
lactic  acid.  Finally,  a  fifth  class  exists,  which  have  no 
power  of  producing  contraction  when  applied  to  either 
muscle  or  nerve ;  such  as  the  fatty  oils  and  turpentine 
(Bennet). 

Thermal  Excitation. 

Different  muscles  also  react  differently  to  the  same  irritant. 
This  is  notably  the  case  in  regard  to  the  effects  of  heat. 
A  moderate  degree  of  heat,  35°  C.  (95°  F.),  increases,  while 
cold  diminishes  the  contractility  of  muscle.  Everyone  is 
familiar   with  the  sluggishness  of   muscular  action   under 


ELECTRIC  EXCITATION.  201 

extreme  cold.  But  an  extreme  heat  absolutely  destroys 
muscular  power  aud  destroys  muscle  by  coagulating  its 
myosin.  Though  myosin  coagulates  at  a  much  lower 
temperature  than  any  other  albumenoid  substance,  the 
degree  of  temperature  at  which  such  molecular  change 
occurs  varies  in  different  species  of  animals.  Thus  myosin 
coagulates  in  the  frog  at  a  temperature  of  34°  C.  (93°  F.), 
in  mammals  at  45°  C.  (113°  F.),  and  in  birds  at  48°  C.  (118.]  ° 
F.).  Subjected  to  a  temperature  of  the  freezing  point  of 
water,  muscle  soon  loses  its  irritability,  but  not  beyond  the 
power  of  perfect  restoration.  But  if  muscle  be  kept  at  a 
temperature  much  below  this  degree,  its  irritability  is  soon 
permanently  destroyed. 

Sudden  changes  of  temperature,  short  of  these  extremes, 
affect  different  muscles  differently.  Weber  and  Calliburces 
long  ago  noticed  the  fact,  wThich  is  now  the  subject  of  daily 
observation  in  physiological  demonstration,  that  the  heart's 
action  when  flagging  with  exhaustion  is  very  decidedly 
stimulated  by  the  application  of  heat,  and  Milne  Edwards 
has  remarked  upon  the  increased  contractility  of  most  of 
the  smooth  fibres,  the  dartos,  the  uterus,  and  the  intestines 
under  the  application  of  heat.  The  muscles  which  are  thus 
excited  to  contraction  are  said  to  be  thermosystaltic,  while 
the  muscles  of  animal  life  are  athermosystaltic.  In  the 
foetus,  which  has  the  circulation  of  a  cold-blooded  animal, 
all  the  muscles  are  thermosystaltic.  Hence  the  efficacy  of 
the  application  of  heat  in  cases  of  still  birth. 

Electric  Excitation. 

But  of  all  irritants  or  stimulants  of  muscular  contractility, 
none  so  nearly  resembles  the  natural  stimulus  of  nerve  force 
as  electricity. 

The  first  recognition  of  the  action  upon  muscles  of  the 
electric  spark  was  made  about  the  middle  of  the  seventeenth 


202  THE  HISTORY  OF  GALVANISM. 

century,  but  it  was  not  until  a  century  later,  September  20, 
1781,  that  Galvani,  Professor  of  Anatomy  and  Physiology 
at  the  University  of  Bologna,  made  the  brilliant  observations 
that  have  immortalised  his  name  in  that  of  the  form  of  elec- 
tricity which  he  employed. 

The  History  of  Galvanism. 

The  history  of  the  discovery  of  galvanism  is  worthy  of 
note,  as  showing  how  the  simplest  observations  lead,  in  a  re- 
flecting mind,  to  the  most  important  results.  The  story 
runs  that  Madame  Galvani  was  preparing  some  recently  de- 
capitated frogs  for  the  dining  table,  when  she  observed  that 
the  apparently  dead  animals  became  convulsed  when 
brought  into  the  neighborhood  of  an  electrical  machine  in 
action.  Prof.  Galvani  next  remarked  that  the  convulsions 
only  ensued  when  a  spark  was  emitted  from  the  machine, 
and  when,  also,  some  metal  substance  came  in  contact  with 
the  exposed  nerves  of  the  frog.  With  a  view  of  discover- 
ing whether  atmospheric  electricity  would  exercise  the 
same  effect,  he  suspended  the  frogs  from  the  iron  trellis 
work  surrounding  the  roof  of  his  house  by  means  of  copper 
hooks  "and  saw,  when  they  were  blown  about  by  the  wind, 
that  convulsions  were  caused  whenever  they  came  in  con- 
tact with  the  iron."  Galvani,  however,  made  the  mistake 
of  believing  that  the  electricity  thus  engendered  was  in- 
herent in  the  muscle  and  was  the  source  of  all  vital  action, 
an  error  which  led  to  the  famous  altercation  with  Volta,  ex- 
tending over  a  series  of  years,  conducted  on  both  sides  with 
much  acumen  and  too  much  acrimony,  and  finally 
eventuating  (but  after  Galvani's  death),  as  usual  in  such 
cases,  in  proof  that  each  was  right  and  each  was  wrong. 
"Galvani  was  right  in  maintaining  the  existence  of  an 
animal  electricity,  but  was  wrong  in  believing  it  proven  by 


THE  ACTION  OF  INDUCED  ELECTRICITY.  203 

the  contact  of  two  metals  ;  Volta  was  right  in  maintaining 
that  galvanism  could  be  produced  independently  of  animal 
bodies,  but  was  wrong  in  denying  the  existence  of  animal 
electricity. " 

The  immediate  response  of  living  muscle  to  the  action  of 
electricity  renders  it  a  galvanometer  of  exquisite  sensitive- 
ness. A  frog  prepared  for  experimentation  by  decortication 
and  exposure  of  the  lumbar  nerves,  is  known  as  the  rheo- 
metric  or  galvanoscopic  frog. 

The  Action  of  Induced  Electricity. 

When  an  interrupted  current  of  electricity,  of  whatever 
source,  static,  magnetic,  galvanic,  is  sent  through  a  volun- 
tary muscle,  contraction  of  the  muscle  immediately  super- 
venes. At  least,  it  is  immediate  to  gross  observation.  If, 
however,  the  periods  of  time  be  measured  by  mathematical 
instruments  of  great  nicety,  t>r,  if  the  movement  of  the 
muscle  be  represented  in  exaggerated  form,  as  by  the  attach- 
ment to  it  of  a  long,  delicate,  lever  (the  myograph),  which 
shall  register  the  tracing  of  the  muscle  with  great  accuracy, 
it  is  seen  that  a  short,  but  appreciable,  interval  of  time 
lapses  between  the  application  of  the  stimulus  and  the 
movement  of  the  lever.  This  interval  is  known  as  the 
"pose"  of  the  muscle,  and  occupies  about  the  -^  of  a  second. 
Now  the  lever  is  rather  abruptly  raised,  and  if  its  point  be 
traversed  by  a  sliding  plate,  evenly  run  by  clock-work,  it 
traces  an  obliquely  ascending  arc,  the  elevation  of  which 
corresponds  to  the  force  of  the  contraction.  "When  the 
point  of  the  lever  has  reached  its  highest  point,  in  a  period 
of  time  occupying  about  ^  of  a  second,  the  contraction  has 
ceased,  whereupon  it  falls  in  a  descending  curved  line, 
occupying  in  its  trace  about  -^  of  a  second,  to  its  original 
level.    The  curve  registered  in  this  way  is  known  as  the 


204  THE  ACTION   OF  NERVE   FORCE. 

"muscle  curve."     Thus  the  muscle,  in  its  entire  contraction, 
occupies  the  yV+^o+aV^To  °f  a  second. 

A  second  shock  of  electricity,  of  course,  repeats  these 
phenomena  in  every  particular,  but  if  a  second  shock  shall 
have  been  entered  before  entire  relaxation  has  occurred,  the 
muscle  curve  will  not  fall  to  its  original  level  before  it  is 
caught  again,  so  to  speak,  and  forced  to  rise.  Now,  if  re- 
peated shocks  be  entered  rapidly,  but  not  too  rapidly,  the 
curve  will  be  held  high  on  the  plate,  and  the  rise  and  fall  of 
each  contraction  and  relaxation  will  be  very  slight.  At  ten 
shocks  (vibrations  of  the  fork)  per  second,  the  distinct 
effects  of  each  still  remain  visible ;  at  fifteen,  the  individual 
shocks  begin  to  become  fused,  and  at  twenty  vibrations  to 
the  second,  the  muscle  is  held  permanently  contracted. 
This  constitutes  what  is  known  as  tetanus.  We  use  the 
ordinary  Faradic  battery  as  a  good  instrument  for  "the 
exhibition  of  the  spasmodic  contractions  of  individual 
shocks,  and  the  small  French  Voltaic  battery  to  exhibit 
the  tetanising  effects  of  rapidly  succeeding  shocks. 

The  Action   of  Nerve  Force. 

The  constant  current  of  electricity  produces  contraction 
in  the  muscle  only  at  the  moment  of  making  and  breaking 
contact.  During  the  steady,  constant,  flow  of  the  electric 
force,  the  muscle  remains  perfectly  passive  and  unaffected. 
When  muscle  contracts  physiologically,  that  is,  under  the 
influence  of  nerve  force,  it  is  held  contracted,  as  in  tetanus, 
until  the  stimulus  from  the  nerve  is  voluntarily  or  invol- 
untarily withdrawn.  The  inference  is,  hence,  plain,  that 
norve  force  is  sent  to  muscle,  not  in  a  continuous,  but  in  an 
interrupted  current.  And  as  muscle  does  not  contract 
spasmodically  under  nervous  force,  this  force  must  be 
transmitted  to  muscle  in  a  series  of  vibrations,  numbering 
at  least  twenty  to  the  second. 


THE  MUSCULAR   WAVE.  205 

The   Sound  of  Muscle    Contraction. 

What  lends  to  this  inference  additional  support,  is  the  fact 
that  muscle,  in  contracting,  produces  sound.  Sound  implies, 
of  course,  a  series  of  vibrations.  A  body  at  perfect  rest 
emits  no  sound.  Muscle  emits  a  sound  which  is  distinctly 
audible.  If  a  stethoscope  be  placed  over  a  contracting 
biceps,  a  humming  sound  is  distinctly  perceived,  or  if,  in 
the  stillness  of  the  night,  the  ears  be  stopped  with  the 
fingers  and  the  jaws  firmly  closed,  the  sounds  of  the  power- 
ful flexors  of  the  jaw  may  be  clearly  perceived.  The  note 
emitted  by  the  sound  of  contracting  muscle  is  always  the 
same.  It  indicates  twenty  vibrations  to  the  second.  This 
is  the  "music  of  motion,"  and 

"Such  are  the  subtle  strings  in  tension  found 
Like  those  of  lutes,  to  just  proportion  wound 
Which  of  the  air's  vibration  is  the  force."         Blackmore. 

The  Muscular    Wave. 

From  what  has  been  already  said,  it  is  plain  that  muscle 
has  no  power  to  contract  of  itself.  In  other  words,  muscle 
possesses  no  automatism.  It  has  the  capacity  for  work,  but 
exhibits  this  capacity  only  under  stimulus.  This  stimulus 
is  imparted  physiologically,  as  we  have  seen,  only  by  the 
nervous  system,  and  is  manifested  first,  as  would  have  been 
assumed,  at  the  points  where  the  nerve  reaches  the  muscle. 
As  a  nerve  is  about  to  be  distributed  to  muscle,  it  subdivides 
into  a  leash  or  into  branches,  like  a  whip-lash  with  many 
tails,  and  these  branches,  containing  at  their  termination  in 
the  muscle  only  the  essential  conducting  element  of  nerve 
force,  fuse  with  an  accumulation  of  sarcolemmar  nuclei, 
which  are  collected  to  form  a  disc  or  plate  at  certain  points 
on  the  surface  of  the  muscle  fibre.  The  muscle  fibre  begins 
to  swell  in  thickness  at  this  point,  and  at  other  similar 


206  INDEPENDENCE   OF   MUSCULAR  FORCE. 

points,  so  as  to  present  the  appearance  of  a  beaded  rod. 
The  beads  or  swellings,  under  continuing  contraction,  con- 
tinue to  increase  in  size,  so  that  the  intervals  are  absorbed,  so 
to  speak,  in  contiguous  enlargements,  until  the  whole  fibre  and 
the  whole  muscle  is  gathered  up  into  a  globar  or  rather  a 
fusiform  mass.  By  means  of  ingeniously  contrived  appar- 
atus, Aeby  was  able  to  estimate  the  velocity  of  the  muscular 
wave  at  40  inches  (1  meter)  per  second,  a  rate,  thus,  much 
more  rapid  than  ordinary  protoplasmic  (e.  #.,  ciliary) 
motion,  but  much  less  rapid  than  nerve  force.  Hence 
muscular  force  is  not  nerve  force.  Nerve  force  is  the  sepa- 
rate force  which  evokes  muscular  force. 

Independence  of  Muscular  Force. 

The  independence  of  muscular  force  is  likewise  proven  by 
the  fact  that  muscle  removed  from  all  connection  with  the 
nervous  system  will  still  respond  to  other  stimulus.  Still 
living  muscle  will  continue  to  contract,  under  stimulus, 
when  entirely  removed  from  the  body,  and  will  continue  to 
respond  to  artificial  excitation  in  the  body  after  the  nerve 
force  has  been  annulled  by  section  of  the  nerve  fibre  and 
death  of  its  peripheral  end.  Thus  Longet,  in  1841,  cut  the 
facial  nerve  and  found  that  it  lost  its  irritability  entirely  in 
four  days.  But  the  muscles  supplied  by  this  nerve  con- 
tinued contractile  for  more  than  twelve  weeks. 

Action  of  Sulphocyanide  of  Potassium  and  Curare. 

But  the  most  striking  and  irrefragable  proof  of  the  inde- 
pendence of  muscular  contractility  was  established  by 
Claude  Bernard  in  the  discovery  of  the  action  of  an 
agent,  the  sulphocyanide  of  potassium,  which  paralysed 
muscular  irritability  without  affecting  that  of  the  nerve, 
and  of  the  action  of  an  agent,  woorara,  which  paralysed 
nervous  irritability  without  affecting  that  of  the  muscle. 


THE  ACTION  OF    CURARE.  207 

The  solution  of  sulphocyanide  of  potassium  (KCyS)  is 
made  by  simply  boiling  sulphur  with  a  solution  of  pure 
cyanide  of  potassium.  It  is  used  in  commerce  as  the  basis 
(with  mercury)  for  the  manufacture  of  the  dangerous  little 
fire  cones,  known  as  Pharaoh's  serpents.  When  a  small 
quantity  of  the  sulphocyanide  of  potassium  is  introduced 
beneath  the  skin  of  the  frog,  the  muscular  system  becomes 
entirely  paralysed  to  every  other  stimulus  than  that  trans- 
mitted through  the  nerves.  Electricity  applied  directly  to 
the  muscle  now  produces  no  effect,  but  still  exerts  its  power 
upon  the  muscle  when  applied  directly  to  the  nerves  dis- 
tributed to  the  muscle. 

The  real  nature  and  composition  of  woorara  (curare)  con- 
tinue unknown.  It  is  an  extract  of  one  or  several  vege- 
tables, and  probably  contains  also  several  animal  products. 
The  Indians  dip  the  points  of  their  arrows  in  it  and  thus 
kill  their  foes  by  the  slightest  wounds.  They  use  it  also  for 
hunting  purposes,  experience  having  taught  them  its  per- 
fect innocuousness  when  introduced  into  the  stomach,  not- 
withstanding its  deadly  effects  upon  the  blood.  The  flesh 
of  animals  killed  by  woorara  is  eaten  with  perfect  impunity, 
while  if  the  poison  be  extracted  from  the  stomach  of  an 
animal  to  which  it  had  been  administered  in  its  food,  and 
injected  into  the  blood  of  another  animal,  it  will  promptly 
exhibit  its  toxic  effect ;  proof  that  the  immunity  which  the 
stomach  enjoys,  is  not  due  to  neutralisation  of  the  poison 
by  the  gastric  j  uice,  but  to  refusal  to  absorb  it.  In  this  re- 
spect it  resembles  the  poison  of  snakes,  on  which  account  its 
active  principle  has  been  supposed  to  be  the  venom  of  the 
crotalus  (Fournie). 

When  a  small  quantity  of  curare  is  introduced  beneath 
the  skin  of  an  animal,  it  paralyses  all  the  motor  nerves, 
but  has  no  effect  whatever  upon  the  sensitive  nerves,  or 
upon  the  muscles.     Electricity  or  other  excitant  may  now 


208  THE  GENERATION   OF  HEAT. 

be  applied  to  the  nerves  without  the  least  effect  upon  the 
muscle,  but  the  muscle  still  continues  to  respond  to  direct 
excitation  of  its  substance.  Curare  acts  by  first  destroying 
the  irritability  of  the  end  plates  of  the  nerves  within 
the  muscles.  Some  of  the  derivatives  of  strychnia, 
ethylstrychnia,  methylstrychnia,  etc.,  produce  the  same  effect. 
Thus  is  absolutely  determined  the  question  of  the  inde- 
pendence of  muscular  contractility  and  its  inherence  in 
muscular  tissue  itself.  But  the  solution  of  this  question  in 
no  way  invalidates  the  fact  that  muscle  never  contracts 
spontaneously,  but  always,  and  only,  in  obedience  to  some 
force  outside  of  the  muscle  substance.  It  is  only  within  a 
very  few  years  that  the  heart  has  been  proven  to  be  no  ex- 
ception to  this  absolute  law.  Bernstein  found  that  if  the 
ventricle  be  compressed  transversely  in  the  middle  with  a 
pair  of  narrow-bladed  forceps,  the  part  beyond  the  line  of 
compression  remains  absolutely  inactive,  though  its  nutri- 
tion is  perfectly  provided  for  by  the  persistence  of  the 
normal  movements  in  the  rest  of  the  heart,  and  Bowditch 
concludes  from  his  experiments  that  "when  after  transverse 
compression  of  the  ventricle,  the  apex,  at  first  brought  to 
rest,  recommences  to  beat,  this  renewal  of  activity  depends 
upon  the  restoration  of  an  imperfectly  destroyed  connection 
between  the  apex  and  the  motor  apparatus  at  the  base  of 
the  heart." 

The  Generation  of  Heat. 

Muscle,  in  contracting,  develops  heat.  Every  one  is 
familiar  with  the  fact  that  the  temperature  of  the  body  in- 
creases during  exercise.  In  the  absence  of  fire,  we  depend 
upon  exercise  to  furnish  means  of  sustaining  the  body  heat 
under  exposure  to  cold.  But  exercise  also  increases  the 
activity  of  the  circulation,  of  respiration,  etc.,  as  more 
probable  sources  of  the   origin  of    heat.     To  determine 


THE  GENERATION  OF  ELECTRICITY.  209 

whether  muscle  developed  heat,  and  if  so,  its  exact  amount, 
Becquerel  and  Brechet  made  use  of  an  instrument  known  as 
a  thermo-multiplicator,  so  constructed  as  to  cause  wide 
deviations  of  a  needle  under  fractions  of  a  degree  of  tempera- 
ture. A  needle  connected  with  the  apparatus  was  now 
stuck  into  the  biceps  muscle  of  a  man.  When  the  biceps 
contracted,  it  registered  a  deviation  corresponding  to  an 
increase  of  1°  C.  Helmholtz  experimented  with  frog's 
muscle  connected  with  the  body  only  by  its  nerve ;  removed, 
thus,  from  the  circulation  ;  and  observed,  by  means  of  a  very 
sensitive  multiplicator,  a  deviation,  during  contraction,  cor- 
responding to  an  elevation  of  0.1°  C.  In  a  frog's  muscle  a 
single  contraction  may  develop  0.005°  C,  which  tetanus  may 
increase  to  0.15°  C.  Beclard,  Thyry  and  Meyerstein, 
Heidenhain,  and,  more  recently,  Fick,  have  all,  by  numerous 
experiments,  demonstrated  the  increase  of  temperature  in 
the  contraction  of  muscle.  Fick  observed  that  when  a 
muscle  was  allowed  to  extend  itself  with  the  weight,  which 
it  had  just  lifted,  still  attached  to  it,  it  gave  out  more  heat 
than  when  it  was  allowed  to  extend  itself  without  the 
weight,  that  is,  with  the  weight  removed  at  the  maximum 
of  contraction.  For,  in  the  sinking  of  the  weight,  while 
muscle  regains  its  former  length,  the  mechanical  work  is 
changed  into  an  equivalent  quantity  of  heat.  This  fact, 
Cyon  remarks,  can  only  be  construed  as  an  irresistible  sub- 
stantiation of  the  law  of  the  conservation  of  force  in 
muscular  work.  So,  too,  it  has  been  observed  that  if  a 
muscle  be  held  down  during  contraction,  or  during  the 
effort  of  contraction,  more  heat  is  developed  ;  the  chemical 
force  in  the  muscle  not  being  able  to  expend  itself  in 
mechanical  work,  appears  as  heat. 

The  Generation  of  Electricity. 
Lastly,    muscle,    in     contracting,    develops    electricity. 

18 


210  THE  GENERATION  OF  ELECTRICITY. 

When  this  fact  was  first  discovered  by  Galvani,  the  most 
extravagant  conceptions  were  entertained  as  to  its  signifi- 
cance. It  was  believed  that  animal  electricity  was  the 
fons  et  origo,  the  supreme  source  and  cause  of  all  vitality. 
This  idea  seems  to  us  now  sufficiently  absurd,  but  in  view 
of  our  so  recent  release  from  the  thralldom  of  a  mysterious 
"vital  force,"  that  refuge  of  ignorance  and  phantom  of 
superstition,  infinitely  more  illusive  and  delusive  than 
animal  electricity,  which  has  at  least  demonstrable  existence, 
we  may  not  cast  reflections  upon  the  credulity  of  the  older 
physiologists.  The  electricity  evolved  from  muscle  may  be 
readily  demonstrated  by  applying  the  exposed  nerve  of  the 
frog's  leg  to  the  separated  muscle  of  the  thigh,  so  that  the 
nerve  will  touch  the  muscle  at  two  points  only,  viz.,  on  the 
surface  of  the  muscle,  and  on  its  cut  end.  By  arranging  a 
series  of  separate  thighs  (frogs),  so  that  one  rested  into  the 
other  like  a  set  of  cups,  the  outside  of  one  resting  in  the  in- 
side of  the  one  below  it,  Matteucci  constructed  a  so-called 
frog  battery.  By  connecting  with  wires,  attached  to  a 
galvanometer,  the  two  end  thighs,  of  a  series  of  ten,  an 
electric  current  was  obtained,  sufficient  to  deflect  the  needle 
thirty  degrees. 

Our  positive  knowledge  regarding  the  electric  currents  in 
muscle  and  nerve  dates  from  the  remarkable  experiments  of 
Du  Bois-Reymond,  of  Berlin.  This  observer  has  shown  that 
t'.ic  current  of  electricity  runs,  in  all  cases,  from  the  surface 
to  the  cut  end  of  a  muscle,  and  this  is  the  case  whether  the 
observation  be  made  upon  a  whole  muscle  or  upon  any  part 
of  a  muscle.  The  surface  is  hence  positive,  and  the  cut  end 
negative.  So  soon  as  the  muscle  is  called  into  action,  the 
strength  of  this  current  is  at  once  diminished,  and  the 
current  is  hence  said  to  experience  a  "negative  variation." 
This  diminution  of  the  current  during  the  contraction  of 
muscle,  is  a  result  which  would  have  been  premised  from  our 


DU  bois-tieymond's  theory.  211 

knowledge  of  the  law  of  conservation  of  force.  For  the 
electricity  evolved  from  muscle  has  its  origin  in  the 
chemical  changes  constantly  at  work  in  the  muscle,  and  if 
these  chemical  changes  may  expend  their  force  in  muscular 
work,  the  electric  current  must,  of  necessity,  be  diminished 
in  strength. 

Du  Bois-ReymoncVs  Theory  of  Muscular  Action. 

In  order  to  explain  the  peculiar  direction  assumed  by  the 
electric  current  in  muscle,  Du  Bois-Reymond  has  proposed 
the  theory  that  muscle  fibre  is  composed  of  molecules,  each 
of  which  has  an  equatorial  belt  or  zone  manifesting  positive 
electricity,  and  two  polar  zones  manifesting  negative 
electricity.  The  equatorial  zones  being  always  on  the  sur- 
face, no  matter  how  much  the  muscle  be  divided  longitu- 
dinally, will  always  exhibit  positive  electricity,  while  the 
polar  zones,  being  exposed  by  transverse  section,  will 
always  exhibit  negative  electricity.  Hence  the  current 
must  pass  from  the  natural  or  artificial  surface  of  muscle 
towards  its  transversely  cut  end.  The  subject  of  muscle 
electricity  is  still  in  its  infancy,  and  while  it  is  possible  that 
further  investigations  may  yield  results  of  the  highest  prac- 
tical interest,  regarding  the  molecular  construction  and 
essential  action  of  muscle,  it  may  "not  be  claimed  that  they 
have  as  yet  been  obtained.  It  is  stated,  indeed,  that  the 
mere  shape  of  the  pieces  of  muscle  employed  in  experi- 
ments has  great  effect  upon  the  direction  of  the  current. 
And  it  is  stated  by  Kiiss  that  "a  muscle  may  possess  its 
normal  electric  current  and  yet  have  lost  all  its  other 
properties;  thus  poisons,  which  kill  the  muscle,  have  not 
always  the  same  effect  upon  its  electro-motor  power  ;  finally, 
similar  currents  have  been  observed  in  living  tissue  of 
various  kinds,  even  in  vegetables,  as,  for  instance,  in  pieces 
of  the  pulp  of  a  potato." 


212  RIGOR  MORTIS. 

Rigor  Mortis. 

We  may  take  up  now  the  changes  which  muscle  under- 
goes at  and  after  death.  It  is  a  familiar  fact  that  death  of 
all  the  tissues  does  not  take  place  simultaneously.  For  a 
long  time  after  volitional  or  reflex  control  has  been  lost,  by 
suspension  of  volition  or  reflex  action,  a  muscle  will  still 
continue  to  respond  to  artificial  stimulus.  The  muscles  of 
cold  blooded  animals  remain  irritable  for  8-10  days  after 
the  death  of  the  animals,  and  under  favorable  circumstances, 
much  longer.  Thus  my  colleague,  Dr.  Longworth,  reported 
to  our  Academy  of  Medicine,  the  continuing  pulsation  of 
the  heart  of  a  boa  constrictor  twenty-one  days  after  it  had 
been  sent  in  dead  from  the  Zoological  Garden  for  purpose 
of  post-mortem  examination,  and  Redi  saw  contractility 
persist  in  a  tortoise  twenty-three  days  after  death.  But  the 
muscles  of  warm  blooded  animals  lose  their  irritability  in  a 
few  hours,  or  at  most,  in  a  few  days.  The  muscles  of  birds 
cease  to  respond  to  irritation  sooner  than  those  of  mammals. 

The  precise  time  at  which  muscle  irritability  is  lost, 
depends  then  upon  the  nature  of  the  animal.  It  depends 
also  upon  surrounding  conditions.  Thus  it  is  preserved 
longest  at  a  temperature  of  0°  C. ;  a  lower  temperature 
freezes  muscle  and  thus  speedily  destroys  its  irritability, 
and  a  much  higher  temperature  hastens  chemical  change 
and  thus  exercises  the  same  effect. 

The  death  of  muscle  is  characterised  by  a  peculiar  change 
in  its  substance.  It  becomes  gradually  more  dense  and  less 
extensible.  When  this  stage  has  wholly  developed,  muscle 
is  said  to  be  in  the  stage  of  cadaveric  rigidity  or  rigor 
mortis.  The  immediate  cause  of  these  physical  changes  is 
the  coagulation  of  the  myosin,  or  muscle  protoplasm. 
Myosin  clots  after  death  just  as  fibrin  clots  in  the  blood, 
and  thus  change**  the  consistency  of  muscle  substance.     The 


RIGOR  MORTIS.  213 

members  of  the  body  must  be  composed  shortly  after  death 
to  anticipate  these  changes  by  a  fixation  in  the  position  in 
which  it  is  intended  they  shall  remain.  For,  after  rigidity 
is  developed,  the  posture  of  the  body,  or  the  position  of 
members,  can  be  changed  only  with  considerable  force. 

Rigidity  first  establishes  itself  in  the  muscles  of  the  neck 
and  jaws,  next  in  those  of  the  trunk  and  lastly  in  those  of 
the  upper  and  lower  extremities,  and  it  is  in  this  order  or 
sequence  that  it  gradually  disappears  to  putrefactive 
change.  It  never  occurs  immediately  after  death,  and  is 
never  entirely  absent,  though  it  may  be  comparatively 
slight  in  degree.  Involuntary  muscle  experiences  the  same 
change,  but  at  a  later  period.  The  very  last  muscle  to  sur- 
render to  rigor  mortis  is  the  right  auricle  of  the  heart,  and 
because  this  fact  was  first  noticed  by  Haller,  this  organ  was 
complimentarily  designated  the  "ultimum  moriens  Halleri" 

Such  radical  change  occurs  in  muscle  substance  when 
undergoing  rigor  mortis,  that  it  is  only  at  the  commence- 
ment of  this  process  that  its  irritability  can  be  restored  by 
the  transfusion  of  fresh  blood.  Preyer  was  able,  however, 
by  dissolving  the  coagulated  myosin  with  a  solution  of 
.common  salt,  and  then  injecting  blood,  to  restore  irritability 
to  muscle  in  cadaveric  rigidity.  This  recovery  of  tone 
was,  of  course,  due  to  the  fact  that  all  the  myosin  does  not 
coagulate  at  once ;  enough  for  purposes  of  demonstration 
still  remains  fluid,  and  able  to  act,  when  relieved  from  the 
clogging  action  of  the  coagulum  about  it. 

Post-mortem .  rigidity  sets  in  very  speedily  in  muscles 
whose  tone  has  been  exhausted  just  before  death,  as  in 
hunted  animals,  or  after  poisoning  with  strychnia,  tetanus 
from  septic  disease,  or  other  cause.  It  is  stated  by  Sommer 
that  it  never  manifests  itself  sooner  than  seven  minutes  'cr 
later  than  ten  hours.  Although  army  surgeons  have  con- 
tended, from  observations  of  the  postures  of  soldiers  killed 


214  POST-MORTEM  CHANGES  IN  MUSCLE. 

on  the  field  of  battle,  that  rigidity  is  occasionally  immediate, 
it  is  known  that  some  interval  of  time  always  intervenes. 
But  in  cases  of  very  sudden  death  the  interval  is  very  short. 
As  a  rule,  the  more  slowly  it  develops,  the  longer  it  lasts. 
In  cases  of  death  by  stroke  of  lightning  or  poisoning  by 
prussic  acid,  its  persistence  is  so  short  as  to  have  given  rise 
to  the  erroneous  belief  that  it  had  not  occurred  at  all.  We 
know  of  no  agent  that  may  temporarily  induce  it  after  the 
manner  of  the  drug  which  the  friar  gave  to  Juliet,  that 

"Each  part  deprived  of  supple  government, 
Shall  stiff  and  stark  and  cold  appear  like  death." 

Post-Mortem  Changes   in  Muscle. 

Very  curious  changes  sometimes  occur  in  muscle  after 
death.  In  the  presence  of  much  moisture,  bodies  are  occa- 
sionally completely  saponified,  converted  into  adipocire,  and 
are  thus  indefinitely  preserved.  Or,  muscle,  with  other  soft 
parts,  may  become  dried  up,  mummified,  and  be  thus  pre- 
served for  thousands  of  years.  Both  these  processes,  as  well 
as  that  of  calcification  (lithopaedion),  may  occur  also  in  the 
foetus  in  utero.  But,  in  the  rule,  muscle  substance  under- 
goes gradual  liquefaction  and  resolution  by  ordinary  putre- 
factive changes.  But  all  the  muscles  do  not  suffer  dissolu- 
tion to  the  same  degree.  Thus  the  walls  of  the  aorta  persist 
long  after  the  smaller  vessels  and  the  voluntary  muscles 
have  disappeared.  The  tissue  or  structure  which  survives, 
or  rather  persists,  the  longest,  is  the  uterus,  and  it  is  to  call 
your  attention  to  this  fact,  which  is  of  great  value  from  a 
medico-legal  point  of  view,  that  I  make  mention  of  a  subject 
not  strictly  physiological.  The  uterus  remains  fresh  and 
firm  long  after  destruction  of  all  other  soft  parts  in  the 
body.  In- the  midst  of  universal  decomposition  it  may  still 
be  removed  from  the  body  in  its  entirety,  be  opened  and  ex- 
amined, and  thus  the  presence  or  absence  of  pregnancy  at 


THE  FUEL  OP  MUSCLE.  215 

or  prior  to  death,  established.  The  uterus  of  the  new-born 
child  persists  in  the  same  way.  In  his  monumental  work  on 
Legal  Medicine,  Casper  details  cases  of  extreme  interest  in 
which  the  persistence  and  appearance  of  the  uterus  furnished 
positive  evidence  concerning  conditions  at  the  time  of 
death. 

The  Fuel  of  Muscle. 

The  muscle  machinery  is  no  more  capable  of  action 
without  food  than  a  steam  engine  without  fuel,  and  the 
promptitude  and  power  of  muscular  action  depends,  as  in 
the  machine,  upon  two  factors:  (1),  upon  the  character  of 
the  fuel,  and  (2),  upon  the  capacity  of  the  muscle  to  convert 
latent  into  active  force.  The  fuel  from  which  the  most 
force  can  be  evolved  is  that  which  contains  the  most 
combustible  material.  The  most  combustible  material  (that 
is  least  expensive)  is  carbon.  The  fuel  which  contains  the 
most  carbon  is  coal,  hence  coal  is  the  best  fuel  for  the 
engine.  The  food  which  contains  the  most  carbon  is  fat, 
and  the  various  hydrocarbons,  hence  these  aliments  form 
the  best  fuel  for  muscular  work.  It  has  always  been 
maintained  up  to  very  recent  years  that  muscle  consumed 
its  own  substance  in  its  work,  but  this  view  was  easily  dis- 
proven  by  the  observation  that  the  products  of  muscular 
work  are  not  products  of  muscular  consumption.  Muscle 
protoplasm  is  largely  composed,  as  we  have  seen,  of  myosin, 
a  pecular  albumenoid  substance,  which  occupies  a  place 
between  fibrin  and  globulin.  Oxidation  of  myosin,  which 
with  all  the  albumenoids  is  a  nitrogenised  matter,  must 
yield  nitrogenised  products  (urea)  in  the  excretions.  But 
observation  has  shown  that  the  urea  is  not  increased  in  the 
urine  as  the  result  of  muscular  work.  This  conclusion  has 
been  reached  from  many  directions,  but  nowhere  so  decisively 
as  from  the  observations  of  Fick  and  Wiscilenus,  who  as- 


216  THE  OXYGEN  SUPPLY. 

cended,  fasting,  a  high  mountain  in  the  Bernese  Alps, 
carefully  measuring  the  urine  voided  at  every  stage  of 
progress,  for  its  quantity  of  urea.  The  quantity  of  urea 
was  not  increased  by  this  severe  physical  exercise,  but 
the  exhalation  of  carbonic  acid  gas  from  the  lungs  and 
skin  was  very  markedly  increased,  proof  that  the  material 
used  as  fuel  was  not  the  muscle  substance  itself,  but  the 
hydrocarbons  of  the  blood.  Indeed,  Mayer  has  made  a 
calculation  showing  that  if  muscle  consumed  itself  in  action 
the  whole  muscular  system  would  be  burnt  up  (oxidised)  in 
just  eighty  days. 

But  though  muscle  machinery  does  not  use  up  itself  as 
fuel  any  more  than  any  other  engine,  it  does,  like  every 
other  engine,  undergo  the  wear  and  tear  of  daily  use  and 
thus  experience  waste  in  slight  degree.  That  this  waste 
may  be  repaired  and  the  physiological  integrity  of  the 
muscles  preserved,  nitrogenous  food  is  also  a  necessity. 

The  Arab,  says  Donders,  never  lets  his  horse  eat  grass 
and  hay  to  satiety.  Its  chief  food  is  barley,  and  in  the 
wilderness  it  gets  milk,  and  if  great  effort  is  required,  even 
camels  flesh.  A  super-abundance  of  nitrogenous  food  is 
found  for  animals  in  corn,  which,  notwithstanding  its  excess 
of  hydro-carbons,  contains  more  albuminates  than  any 
other  vegetable  food.  Oats,  too,  furnish  horses  an 
abundance  of  nitrogenous  matter,  and  jockeys  have  a 
saying,  on  witnessing  spirited  work  in  horses,  that  they 
"feel  their  oats." 

The  Oxygen  Supply. 

The  food  thus  furnishes  the  oxidisable  material.  Then 
muscle  must  also  receive  abundant  supply  of  oxygen.  We 
have  already  seen,  that  this  supply  is  brought  to  muscle 
by  the  blood,  which  reaches  it  red  and  leaves  it  blue.  If  the 
muscle  be  at  rest,  however,  the  blood  is  so  little  deoxygenated 


THE    MUSCLES   AS   LEVERS.  217 

that  its  escaping  blood  preserves  its  arterial  hue.  It  is  said 
that  oxygen  administered  roughly,  as  by  the  injection  of  a 
highly  oxygenated  substance,  permanganate  of  potash,  for 
instance,  will  restore  irritability  to  a  dying  muscle,  and  it 
is  well  known  that  the  transfusion  of  fresh  blood  will,  by 
means  of  its  oxygen,  effect  this  result  up  to,  and  even  after  the 
commencement  of,  cadaveric  rigidity. 

Dependence  of  Muscle  upon  Blood. 

The  necessity  of  a  continuous  supply  of  material  for 
consumption  (food),  and  material  for  consuming  (oxygen), 
by  the  blood,  is  conclusively  demonstrated  by  the  observa- 
tion of  the  effects  attending  ligation  of  the  vessels  supplying 
muscles.  Thus  Longet  tied  the  abdominal  aorta  in  five 
dogs  and  found  that  voluntary  motion  ceased  in  about  a 
quarter  of  an  hour,  and  response  to  artificial  stimulus  in  two 
and  a  quarter  hours.  When  the  ligature  was  removed, 
irritability  to  stimulus,  and  afterwards  voluntary  motion, 
shortly  returned.  Brown-Sequard  made  some  similar  ex- 
periments of  more  striking  nature  upon  the  human  body. 
In  the  cases  of  two  decapitated  criminals,  he  transfused 
fresh  blood  into  the  arteries  of  the  hand,  thirteen  hours  and 
ten  minutes  after  death,  when  all  muscular  irritability  had 
disappeared,  and  cadaveric  rigidity  was  quite  marked,  and 
found  that  it  reappeared  and  could  be  demonstrated  in  all 
but  two  of  the  muscles  of  the  hand.  On  a  subsequent 
occasion,  he  used  the  defibrinated  blood  of  the  dog  with  the 
same  effect  (Flint). 

The  Muscles  as  Levers. 

Let  us  now  look  at  the  muscles  from  a  purely  mechanical 
point  of  view,  viz.,  as  levers.  Those  of  us  who  are  at  all 
acquainted  with  the  laws  of  mechanics  are  aware  that  there 
are  three  different  classes  of  levers.    The  first  is  represented  in 

19 


218  THE  ABSOLUTE  POWER  OF  MUSCLE. 

using  the  common  crowbar,  or  in  working  the  pump  handle, 
or  in  raising  coals  with  a  poker  in  a  grate.  The  fulcrum 
rests  between  the  power  and  the  weight.  Though  there  is 
in  this  form  of  lever  considerable  power,  there  is  not  much 
range  of  movement.  The  chief  advantage  of  this  lever  is 
celerity  of  action.  A  typical  illustration  of  this  form  of 
lever  in  the  body  is  the  action  of  the  muscles  which  move 
the  head  upon  the  spine.  The  muscles  of  the  neck  constitute 
the  power,  the  head  is  the  weight,  and  the  spine  is  the 
fulcrum. 

In  a  lever  of  the  second  class,  the  weight  is  between  the 
power  and  the  fulcrum,  as  in  the  case  of  trundling  the 
common  Avheelbarrow.  Here  there  is  great  power,  but 
little  velocity,  and  less  range.  The  best,  and  almost  the 
only,  example  of  this  lever  in  the  body,  is  the  action  of  the 
tendon  of  Achilles  in  lifting  the  whole  body  in  walking. 
The  muscle  of  the  calf  form  the  power,  the  body  is  the 
weight,  and  the  toes  are  the  fulcra. 

In  the  lever  of  the  third  class  the  power  is  between  the 
weight  and  the  fulcrum.  It  is  represented  in  lifting  a  ladder 
up  against,  or  away  from,  a  wall.  There  is  here  but  little 
advantage  for  power,  there  is  less  velocity,  but  there  is  wide 
range.  The  free  end  of  the  ladder  has  enormous  sweep. 
The  lever  of  the  third  class  is  the  feeblest  of  all  the  levers, 
but  every  thing  here  is  sacrificed  to  range.  This  is  by  far 
the  most  common  form  of  lever  in  the  body,  and  is  typically 
represented  in  the  action  of  the  biceps  brachialis. 

The  Absolute  Power  of  Muscle. 

The  absolute  power  of  muscle  is  dependent,  as  would  have 
been  inferred,  upon  its  bulk,  as  exhibited  on  cross  section, 
and  is  determined  by  observing  the  weight  which  it  will 
lift.  It  has  been  observed  that  the  power  of  contraction  is 
at  its  maximum  on  the  beginning  of  shortening,  and  thus 


THE  POWER   OF   MUSCLE   IN   GENERAL.  219 

Weber  has  been  able  to  fix  the  absolute  power  of  one  square 
centimetre  of  frogs  muscle  (hyoglossus),  under  the  most 
favorable  circumstances  at  0.G02  kilogrammes  (24  oz.). 
Rosenthal  succeeded  later  in  obtaining  better  results,  viz., 
for  the  same  quantity  of  muscle  a  little  over  one  kilogramme 
(35  oz.).  Weber  found  that  muscle  exerted  its  maximum 
effect  when  he  loaded  the  same  piece  of  muscle  with  only 
450  grammes  (15  oz.).  The  muscle  then  lifted  93  times  its 
weight  15  millimeters  (006  in.)  high.  In  subsequent  experi- 
mentation on  man,  Weber  found  that  the  absolute  power  of 
human  muscle  is  very  much  greater.  Thus  a  square  centimeter 
(0.4  in.)  of  the  gastrocnemius  muscle  of  man  has  an  absolute 
power  of  700-1087  grm.  (24-38oz.).  Henke  and  Kosterhave, 
also,  obtained  better  results,  observing  that  a  square  centi- 
meter of  muscle  from  the  thigh  had  a  power  5.9  kilogrammes 
(215  oz.)  and  from  the  arm  of  8  kilogrammes  (282  oz.), 
a  difference,  as  Bruecke  observes,  which  was  clearly  due  to 
difference  in  the  muscular  power  of  the  individuals  under 
observation. 

The  Power  of  Muscle  in  General. 

The  general  power  or  force  of  muscles  may  be  readily 
estimated  by  means  of  an  instrument  first  devised  by 
Regnier,  the  dynamometer,  which  consists  of  a  steel  spring 
whose  compression  (by  the  hand  or  other  group  of  muscles), 
moves  a  needle  along  a  scale  graduated  to  represent  equiva- 
lents of  weight.  This  instrument  of  precision  is  of  great 
value  in  clinical  medicine  in  enabling  the  physician  to 
accurately  guage  the  effects  of  treatment  of  paralysed 
muscles  and  has  enabled  physiologists  to  make  the  observa- 
tion that  the  muscles  differ  in  force  in  different  individuals, 
and  in  different  muscles  in  the  same  individual  at  different 
times.  Thus  Koster  found  that  the  power  from  the  same 
sections,  was  for  the  biceps  brachialis  17  kilogrammes,  for  the 


220  THE  DIFFERENCE  IN   THE   SEXES. 

gastrocnemius  10  kilogrammes  and  for  the  posterior  tibial 
only  2  kilogrammes.  The  difference  in  different  individuals 
is  generally  determined  after  the  method  first  employed  by 
Begnier,  which  consists  in  lifting  a  weight- from  the  ground 
between  the  feet.  Quetelet  called  the  force  thus  employed 
the  renal  force,  and  remarked  that  in  youth  it  is  very  slight; 
it  increases  rapidly  up  to  the  age  of  17  or  18  and  attains  its 
maximum  at  25  years.  It  now  remains  stationary  for  a 
time  and  then  declines  markedly  towards  40  years.  It  is 
always  much  less  in  woman  than  in  man.  Desaguliers  states 
that  the  weakest  men  in  health  may  lift  125  lbs.,  and  the 
strongest  of  ordinary  men,  400  lbs.  Topham,  a  so-called 
Sampson,  could  lift  800  lbs. 

Differences  in  the  Sexes. 

It  is  a  subject  of  daily  observation  that  the  female  of  most 
animals  is  capable,  though  of  less  powerful,  of  more  sustained 
effort.  And  this  observation  is  supported  by  anatomical 
and  physiological  differences  in  the  construction  and  action 
of  the  muscles.  The  action  of  muscular  fibres  has  been  not 
inaptly  compared  by  Milne  Edwards  to  the  work  of  a 
number  of  laborers.  The  fibres  are  laborers  in  long  parallel 
lines.  They  do  not  all  pull  at  once  or  with  the  same  degree 
of  exertion.  Hence  the  greater  the  number  of  fibres  the 
greater  the  number  of  rested  or  resting  fibres.  The  muscular 
fibres  in  the  female,  though  individually  smaller,  are 
numerically  greater,  and  hence  the  capacity  for  greater  sus- 
tentation  of  effort. 

Differences  in  Different  Animals. 

C.  Sachs  has  shown  that  the  muscle  caskets  are  smaller  in 
warm  than  in  cold  blooded  animals,  and  smaller  in  cold 
blooded  animals  than  in  anthropods.  In  the  smaller  pieces 
the  physiological  surface  of  tissue  is  increased  and  the 


VELOCITY  AND  DELICACY  OF  MUSCULAR  ACTION.      221 

energy  of  metamorphosis  is  greater.  Hence  the  mechanical 
effects  of  smaller  fibres  is  heightened,  "just  as  a  bundle  of 
magnets  has  a  greater  effect  than  one  massive  magnet  of  the 
same  weight."  The  force  of  the  muscle  of  mammals  is 
hence  greater  than  that  of  the  frog. 

The  remarkable  duration  and  sustentation  of  muscular 
effort  in  birds  thus  also  finds  satisfactory  explanation.  Mon- 
tague, a  celebrated  ormithologist,  estimates  that  hawks  fly 
at  the  rate  of  150  miles  an  hour  and  various  birds  often 
travel  600  to  1000  miles  without  food  in  their  winter  and 
summer  migrations.  But  it  is  in  insects,  in  which  the 
muscle  caskets  have  been  discovered  to  be  minute  structures 
distinctly  suspended  in  fluid,  that  the  force  of  contraction 
is  greatest  in  proportion  to  their  size.  Thus  Dunglison 
states  that  the  lucanus  cervus,  or  stag-beetle,  has  been  known 
to  gnaw  a  hole,  of  an  inch  diameter,  in  the  side  of  an  iron 
canister  in  which  it  had  been  confined,  and  the  same  author 
calls  attention  to  the  persistence  and  apparent  ease  with 
which  flies  will  keep  up  with  the  fleetest  racehorse,  sweeping 
large  circles  about  him  all  the  time.  The  stridulations 
(scrapings  of  wing  covers)  made  by  crickets  and  grasshoppers 
can  be  heard  a  mile,  whence  it  is  estimated  that  if  man 
could  emit  sounds  whose  intensity  should  be  proportionate 
to  his  size,  he  could  make  himself  heard  all  around  the 
earth. 

The  Velocity  and  Delicacy  of  Muscular  Action. 

We  may  not  take  final  leave  of  the  properties  of 
muscle  without  calling  attention  to  the  readiness  of  its  re- 
sponse to  stimulus,  its  capacity  for  swift  repetition  of  con- 
traction, and  the  degree  of  delicacy  and  accuracy  of  its  action 
under  proper  cultivation.  The  ready  response  of  muscle  has 
been  clearly  shown  by  Kronecker  and  Stirling  in  their  demon- 
strations that  muscle  replies  to  stimuli,  which  reach  their 


222      VELOCITY  AND  DELICACY  OF  MUSCULAR  ACTION. 

maximum  in  the  nerve  in  less  than  the  ^rroVoo  Par*  °f  a  second. 
And  as  to  the  capacity  for  swift  repetition  of  contraction, 
these  same  experimenters  quote  the  observations  of  llanvier, 
who  remarked  that  the  pale  muscle  of  the  rabbit  could 
indicate  357  single  contractions  in  a  second,  and  of  Marey 
that  the  common  horse-fly  can  make  voluntarily  330 
movements  of  the  wing  in  a  second.  The  musical  tone 
emitted  by  the  contraction  of  muscle  gives  an  accurate 
estimate  of  the  rapidity  of  muscular  movement.  A  certain 
tone  corresponds,  of  course,  to  a  certain  number  of  vibrations, 
and  hence  it  is  calculated  that  the  wings  of  insects  strike  the 
air  even  many  thousand  times  every  second.  The  finest 
muscular  movements  in  man,  are  those  which  change  the 
position  and  tension  of  the  vocal  cords.  Muller  has  observed 
that  there  are  at  least  240  different  states  of  tension  of  the 
vocal  cords,  and  as  the  whole  variation  is  not  more  than 
one-fifth  of  an  inch,  the  variation  required  to  pass  from  one 
interval  to  another  will  not  be  more  than  x^Vu"  of  an  inch. 

The  quick,  deft  and  delicate  play  of  muscles  is  hardly 
anywhere  better  exhibited  in  man  than  in  the  modulations 
of  the  voice,  in  the  shades  of  expression  of  the  face,  and  in 
the  infinite  variety  of  gesticulation.     Thus: — 

"With  hurried  voice  and  eager  look 
Fear  not,  he  said,         *        *        * 
*        *        *        but  there  the  accents  clung 
In  tremor  to  his  faltering-  tongue."        Scott. 

"The  arched  and  polished  forehead,"  says  Sir  Charles  Bell, 
"terminated  by  the  distinct  line  of  the  brow,  is  a  table,  on 
which  we  may  see  written  in  perishable  characters,  but  dis- 
tinct while  they  continue,  the  prevailing  cast  of  thought." 

"You  may  sometimes  trace 
A  feeling  in  each  footstep,  as  disclosed 
By  Sallust  in  his  Cataline  who,  chased 
By  all  the  demons  of  all  passions  showed 
Their  work  even  by  the  way  in  which  he  trode."        Byron. 


NERVE   AND  ITS  PROPERTIES.  223 


LECTURE    XI. 


NERVE  AND  ITS  PROPERTIES. 

CONTENTS. 

The  Prime  Function  of  Nervous  Tissue— Subordination  to  Other  Tissues 
—Independence  of  Nerve  Force— Genesis  of  Nerve  Force— Arrange- 
ment of  Nerve  Tissue— White  and  Gray  Matter— The  Cerebro-Spinal 
and  Sympathetic  Systems— The  Nerve  Cells— The  Nerve  Fibres— 
The  Neurilemma— The  Axis  Cylinder— The  Gray  Fibres— The  Prop- 
erties of  Nerves — Terminations  of  Sensitive  Nerves— Terminations 
of  Motor  Nerves— Course  of  Nerve  Fibres — Identity  of  Nerve  Fibres 
— Indifference  of  Direction  of  Nerve  Force— The  Chemistry  of  Nerve 
Tissue — The  Action  of  Electricity  upon  Nerve  Tissue— The  Nature 
of  Nerve  Force— Rate  of  Conduction  of  Nerve  Force — Nerve  Force 
and  Electricity— Comparative  Velocity  of  Nerve  and  Other  Forms  of 
Force — The  Reception  and  Perception  of  Impressions — Ancient  Sig- 
nificance of  Nerves— The  Effects  of  Use,    Disuse  and  Age. 

The  primary  object  of  the  nervous  tissue  is  to  link  together 
different  and  often  widely  distant  structures.  The  nervous 
system  is  thus  the  supreme  regulator  of  the  actions  of  the 
body.  It  secures  harmonious  and  consentaneous,  or  coordi- 
nated, operations.  Thus,  if  muscular  activity  is  to  be  in- 
creased (exercised),  the  muscle  substance  must  needs 
have  more  fuel  in  the  way  of  additional  supply  of  blood ; 
it  must  also  have  more  oxygen  to  effect  the  consumption  of 
the  fuel  and  thus  the  liberation  of  additional  force.  Hence 
increased  muscular  activity  implies  accelerated  circulation 
and  accelerated  respiration.  It  is  the  function  of  the  nervous 
system  to  secure  this  consentaneous  and  correspondent 
activity  on  the  part  of  the  heart  and  lungs  as  well  as  on  the 
part  of  the  muscle.  The  nervous  system  has,  at  the  same 
time,  to  regulate  the  activity  of  the  secretory  organs  to 
provide  for  the  escape  of  the  products  of  combustion. 
Complexity  of  organisation  implies,  therefore,  a  nervous 


224         THE  XERVOUS,  STJBSIDARY  TO  OTHER  TISSUES. 

system  in  high  degree  of  development.  An  animal  takes 
rank  in  the  animal  scale,  according  to  the  degree  of  develop- 
ment of  its  nervous  system,  that  is,  according  to  the  quantity 
and  quality  of  its  nervous  tissue. 

The  Nervous,  Subsidary  to  Other  Tissues. 

But  so  much  stress  has  been  laid  upon  the  supremacy  of  the 
nervous  system  that  we  are  apt  to  forget  that  the  rest  of  the 
animal  was  not  constructed  for  the  nervous  system;  the  ner- 
vous system  is  constructed  rather  for  the  benefit  of  the  animal. 
In  fact,  the  nervous  system  stands  towards  the  rest  of  the 
body,  much  in  the  light  of  telegraphy  to  the  inhabitants  of 
a  country.  It  signalises  wants  and  supplies,  regulates 
transmissions,  warns  of  dangers  and  furnishes  intelligence. 
"We  look  back  with  a  feeling  of  pity  and  contempt,  upon 
that  state  of  society  which  enjoyed  no  system  of  telegraphy, 
no  means  of  rapid  communication,  just  as  we  look  down 
upon  animals  not  endowed  with  nervous  tissue,  yet  we  may 
not  forget  that  such  states  of  society,  and  such  kinds  of 
animals,  did  and  do  exist.  The  nervous  system  is  thus  an 
addendum  to  a  higher  grade  of  development.  We  may  not, 
therefore,  look  upon  the  body  as  a  collection  of  cells  attached 
to  the  nervous  tissue  like  the  leaves,  for  example,  upon  the 
trunk  and  twigs  of  a  tree.  On  the  contrary,  it  is  the  nervous 
system  which  is  attached  to  the  cells.  The  nerve  fibres 
are  to  be  looked  upon  as  offshoots  from  the  cells  for  the 
purpose  of  association  and  interaction. 

Independence  of  Nerve  Force. 

It  was  once  believed,  is  taught  now  by  some  meta- 
physicians, that  nerve  force  is  born  in  nerve  centres  and  is 
sent  through  nerve  fibres  to  muscles,  for  instance,  where  it 
acts  as  motion.  That  is,  that  motion  is  only  a  transformed 
nerve   force.     But  the   physiologist  can   not  accept  such  a 


GENESIS  OF  NETtVE  FORCE.  225 

doctrine.  The  nerve  force  is  not  the  fuel  for  the 
muscle.  The  blood,  which  is  the  prepared  food,  is  the  fuel 
that  furnishes  the  muscle  with  force.  The  nerve  force  is 
simply  the  excitant  of  the  muscle.  A  very  small  amount 
of  nerve  force  suffices  to  induce  a  very  great  amount  of 
muscular  force.  Muscle  is  a  machine,  as  we  have  seen,  like 
an  engine.  It  stands  ready  to  act.  There  is  steam  in  the 
boiler,  that  is,  there  is  blood  in  its  substance.  Still  the 
engine  does  not  move.  The  nerve  force  is  the  hand  that 
opens  the  throttle  and  thus  causes  the  machinery  to  move. 
I  might  make  this  point  plainer  by  likening  the  parts  of  the 
body  to  different  branches  of  a  great  army  out  upon  the 
field.  The  nervous  system  is  the  system  of  telegraphy 
which  directs  the  movements  of  the  army.  But  no  one 
would  claim  that  the  movements  of  the  army,  were  trans- 
formations or  transubstantiations  of  the  force  of  electricity 
in  the  battery  of  the  telegraph. 

Genesis  of  Nerve  Force. 

The  nerve  force  is  generated  in  nerve  cells  and  is  conducted 
along  nerve  fibres  or  tubes.  The  study  of  the  nervous  system 
divides  itself,  thus,  physiologically,  into  the  study  of  the 
generators  and  the  conductors.  Cells  never  conduct  and 
fibres  never  generate.  Of  course,  in  using  the  term  generate, 
it  is  not  meant  to  imply  the  creation  of  a  new  force.  Such 
a  conception  is  unscientific,  that  is,  false.  The  nerve  cells 
generate  nerve  force  in  the  sense  in  which  the  cups  of  a 
galvanic  battery  generate  electricity.  The  electricity  from 
galvanism  is  the  result  of  chemical  force  which,  in  turn,  is 
liberated  from  force  latent  in  metals,etc,  stored  up  in  the  past. 
So  the  nerve  cells  are  simply  means  of  transforming  latent 
force  in  the  blood  into  nerve  force.  We  return  again  to  the 
galvanic  battery. 


226  THE  DIVISIONS   OF   NERVE  TISSUE. 

Arrangement  of  Nerve  Tissue. 

The  nervous  system,  we  find  to  be  arranged  like  the 
telegraph  system  of  a  nation  or  state.  There  is  a  great  central 
battery  in  the  capital,  represented  in  the  brain ;  there  are 
smaller  batteries  in  smaller  cities,  as  in  the  separate  collec- 
tions of  nerve  cells  (ganglions)  in  different  organs,  and  where 
distances  are  great,  there  are  reenforcing  batteries,  as  along  the 
sympathetic  and  pneumogastric  nerves.  The  connecting 
wires  are  represented  by  the  nerve  tubes. 

The  Color  of  Nerve  Tissue. 

The  nerve  cells,  en  masse,  present  a  more  or  less  grayish 
hue,  while  the  tubes,  en  masse,  present  a  distinct  white  color. 
Hence  the  terms  gray  matter  and  white  matter.  The 
outside  (cortex)  of  the  brain  and  the  inside  of  the  spinal 
cord  are  mainly  composed  of  cells,  gray  matter,  while  the 
interior  mass  of  the  brain  and  the  exterior  of  the  cord,  are 
composed  of  nerve  fibres,  white  matter.  The  great  ganglia 
at  the  base  of  the  brain  and  the  smaller  ganglia  scattered 
over  the  body,  everywhere,  are  composed  of  both  cells  and 
fibres,  and  show  colors  according  to  the  relative  arrangement 
or  predominance  of  one  or  other  structure. 

The  Cerebro-Spinal  and  Sympathetic  Systems. 

Finally,  the  mass  of  nerve  substance  accumulated  in  the 
cranial  cavity  (the  brain),  and  in  the  great  tube  formed  by 
the  imposition  above  each  other  of  the  arches  of  the  vertebra? 
(the  spinal  cord),  together  with  all  the  nerves  (cranial  and 
spinal)  which  issue  from  their  base  and  sides,  constitute  the 
cerebro-spinal  system  (voluntary),  presiding  over  animal 
life  ;  and  the  ganglionic  masses,  disposed  along  each  side  of 
the  spinal  column  and  extending  into  the  cavity  of  the 
cranium,  connected  with  each  other  and  with  the  cerebro- 


THE   NERVE  FIBRES.  227 

spinal  nerves  by  commissures  and  supplying  motor  and 
sensitive  structures  with  nerve  filaments,  constitute  the 
sympathetic  (involuntary)  system,  presiding  over  vegetative 
life. 

The  Nerve  Cells. 

The  nerve  cells  are  readily  recognised  under  the  microscope 
by  their  irregular,  often  almost  fantastic,  shape,  their  bright 
nucleus  and  nucleolus,  the  amount  of  colored  protoplasm 
(pigment)  which  they  contain,  and  by  the  prolongations 
which  issue  from  their  circumference.  The  prolongations 
are  known  as  poles.  We  observe,  thus,  unipolar,  bipolar, 
multipolar  cells.  Apolar  cells  are  probably  artificial  creations 
that  is,  they  are  results  of  accidents  in  the  examination. 
Else,  having  no  use,  they  would  have  to  be  regarded  as 
foreign  bodies  or  parasites. 

We  may  mostly  recognise  among  the  poles  one  which 
seems  to  be  composed  of  the  essential  element  only  of  the 
nerve  fibre.  It  is,  in  fact,  the  commencing  nerve  fibre.  Some 
of  these  fibres  pass  out  to  the  periphery  as  nerves,  others 
pass  to  other  cells,  connecting  them,  as  commissures.  The 
great  transverse  bridge  of  the  brain,  the  corpus  callosum,  is 
made  up,  for  the  most  part,  of  these  internuncial  fibers, 
connecting  the  cerebral  hemispheres. 

The  Nerve  Fibres. 

Nerves  are  bundles  of  nerve  fibres.  The  ultimate  nerve 
fibre  is  composed  of  three  parts  ;  the  investing  membrane 
neurilemma,  or  tubular  sheath  ;  the  medulla  or  white  sub- 
stance of  Schwann ;  and  the  essential  element  or  axis 
cylinder. 

The  Tubular  Sheath, 

or  neurilemma,  is  an  exceedingly  delicate,  translucent,  but 
highly  resistant  and  elastic  membrane  which  envelops  the 
exterior  of  the  nerve  throughout  its  course.     It  is  absent 


228  THE  AXIS   CYLINDER. 

at  its  inception  from  the  nerve  cell,  it  is  absent  also  in 
places  where  the  nerve  is  already  sufficiently  protected,  in 
cavities  containing  only  nerves,  as  in  the  substance  (white 
matter)  of  the  brain,  and  is  absent  again  where  the  nerve 
passes  to  its  ultimate  distribution. 

The   White  Substance  of  Schwann, 

unfortunately  named  the  medulla,  as  it  does  not  occupy  the 
centre  of  the  tube,  like  the  medulla  of  bone,  is  the  gelati- 
nous, translucent,  substance,  which  composes  the  bulk  of 
the  nerve  fibre.  Shortly  after  death  of  the  nerve,  it  coagu- 
lates to  an  opaque,  white  mass,  and  gives  to  the  nerve  a 
quite  characteristic,  varicose,  appearance.  The  medulla  is 
also  absent  in  central  nerves  and  at  the  beginning  and  end 
of  nerves. 

The  Axis  Cylinder, 

or  axial  band,  is  the  central,  rather  flattened  band  of  clear, 
glassy,  jelly-like  matter,  which  occupies  the  centre  of  the 
nerve  tube.  The  axis  cylinder  is  the  sole  essential  conduct- 
ing element.  The  nerve  issues  from  the  cell  as  the  axis 
cylinder  only,  and  the  medulla  and  the  tubular  sheath  are 
subsequent  additions  of  structure.  At  its  final  distribu- 
tion, the  tubular  sheath  and  medulla  both  disappear,  and 
the  axis  cylinder  alone  passes  to  the  substance  of  the 
muscle,  gland  cell,  hair  bulb,  or  other  structure,  destined  to 
receive  it.  Just  before  its  termination,  the  nerve  divides 
into  a  number  of  branches,  each  commencing  with  a  con- 
striction, and  then  expanding  to  the  full  size  of  the  original 
trunk.  The  axis  cylinder  throughout  exhibits  fine  longitu- 
dinal striae  or  lines,  which  are  supposed  to  represent 
fibrilla;,  like  the  subdivisions  of  muscle  fibre,  and  which  are 
regarded  by  some  histologists  (Schultze)  as  the  ultimate 
elements  of  composition.     When  staining  solutions,  aniline, 


THE   PROPERTIES   OF   NERVES.  229 

carmine,  etc.,  are  brought  into  contact  with  a  piece  of 
living  nerve  under  the  microscope,  it  is  the  axis  cylinder 
alone  which  is  colored. 

The  Gray  Fibres. 

Besides  these  so-called  medullated  fibres,  there  exists  a 
different  variety  of  very  delicate  fibres,  whose  interior  con- 
sists of  a  uniform,  grayish  matter,  and  whose  rather  thick 
sheath  is  provided  with  distinct  nuclei.  Such  fibres  are 
found  only  in  the  sympathetic  system.  They  are  commonly 
known,  from  their  discoverer,  as  the  fibres  of  Remak. 

Most  nerve  fibres  of  the  sympathetic  system,  however, 
are  constituted  upon  the  same  plan  as  those  of  the  cerebro- 
spinal axis,  and  the  several  parts  are  roughly  likened  to  the 
constituents  of  the  sub-marine  cables ;  the  envelop  repre- 
senting the  neurilemma;  the  rubber  or  silk  insulating 
matter,  the  medulla;  and  the  conducting  wire,  the  axis 
cylinder. 

The  Properties  of  Nerves. 

It  is  the  function  of  some  of  the  nerves  to  conduct  from 
the  nerve  cells,  motion,  and  of  other  nerves  to  conduct  to 
the  cells,  sensation.  Other  nerves  passing  to  and  from  the 
various  glands,  to  regulate  secretion,  are  known  as  secretory 
nerves,  and  still  other  nerves  passing  to  the  walls  of  blood- 
vessels, to  regulate  their  calibre,  are  known  as  vaso-motor 
nerves.  The  secretory  and  vaso-motor  nerves,  including 
fibres  of  motion  and  sensation,  are  described  with  the  rest  as 
motory  and  sensory  nerves.  Motor  and  sensitive  nerves  are 
such  exclusively  at  their  origin  from  motor  and  sensitive 
nerve  cells,  but  shortly  after  emergence  from  the  brain, 
spinal  cord,  or  ganglion,  the  fibres  commingle  to  constitute 
what  are  known  as  mixed  nerves. 


230  TERMINATION   OF  SENSITIVE  NERVE  FIBRES. 

Terminations  of  Sensitive  Nerve  Fibres. 

The  nerve  fibres  issue,  as  we  have  seen,  from  the  nerve 
cells,  and  are  to  be  regarded  as  prolongations  from  the 
nerve  cells  to  the  periphery,  where  they  terminate  in  special 
structures. 

The  sensitive  nerves  terminate  in  a  number  of  peculiar 
bodies,  corpuscles  of  Pacini  or  Vater,  corpuscles  of  Meissner 
and  Wagner  (tactile  corpuscles),  and  corpuscles  of  Krause. 
These  bodies  consist  of  rounded  or  ovoid  layers  of  connec- 
tive tissue,  in  the  interior  of  which,  or  upon  the  exterior  of 
which,  the  axis  cylinder  ends.  In  the  case  of  the  large 
Pacinian  bodies,  located  in  the  tendons,  and  especially 
abundant  about  the  mesentery,  the  axis  cylinder  enters  its 
base  and  divides,  in  its  central  cavity,  like  a  fork  with 
prongs,  into  two  or  three  branches,  which  finally  terminate 
in  granular  expansions.  In  the  case  of  the  smaller  tactile 
corpuscles,  found  in  such  abundance  in  the  papillae  in  the 
cutis  vera,  the  axis  cylinder  is  wound  spirally  about  the  ex- 
terior to  finally  terminate  in  a  point  of  extreme  tenuity. 
In  the  still  smaller  corpuscles  of  Krause,  found  in  the 
tongue,  conjunctiva,  glans  penis  and  clitoridis,  and  in  the 
nipple,  surfaces  of  extreme  sensitiveness,  the  axis  cylinder 
penetrates  the  base  and  terminates  in  the  interior  in  a  loose 
coil. 

All  these  bodies  would  seem  to  exist  for  the  purpose,  in 
the  first  place,  of  acting  as  points  oVappui,  points  of  support, 
and,  secondly,  of  increasing  the  area  of  surface  for  the 
termination  of  the  nerve  fibre.  They  officiate  something 
like  the  thickenings  of  epidermis  on  the  feet,  commonly 
known  as  corns.  Though  the  epidermic  mass  has  in  itself 
no  sensation,  it  transmits  pressure  from  every  part  of  its 
surface  to  the  few  nerve  fibres  at  its  base,  and  thus  is  a 
conductor  of  sensation,  which  often  amounts  to  positive 
pain. 


TERMINATIONS   OF    MOTOR   NERVE   FIBRES.  231 

But  the  greater  number  of  the  sensitive  nerve  fibres  pass 
to  terminate  in  the  hair  bulbs.  It  is  a  well-known  fact  that 
we  experience  tactile  sensation  before  absolute  contact  with 
the  skin  is  effected.  The  touch  is  felt  by  the  hairs,  which  so 
uniformly  cover  the  whole  surface  of  the  body.  The  hairs, 
of  course,  simply  transmit  pressure  to  the  nerve  endings  in 
their  bulbs.  These  endings  are  especially  abundant  about 
the  face,  and,  in  the  case  of  some  animals,  are  peculiarly 
large  and  sensitive  about  the  various  vibrissae  or  whiskers. 
Thus,  a  cat  will  readily  wander  about  a  darkened  chamber, 
guided  by  the  exercise  of  the  fine  sense  of  touch  in  its 
whiskers,  which  correspond  to  the  antennae  of  insect  life. 
It  is  said  that  a  kitten  will  thus  find  its  way  even  though 
perfectly  blind.  But  if,  in  addition  to  its  loss  of  sight,  it  is 
made  to  lose  its  whiskers,  it  will  knock  its  head  against 
every  obstacle. 

Nerve  fibres  terminate  in  the  glands  by  effecting  with  the 
secreting  cells  the  most  intimate  union.  Ends  of  nerve 
fibres  have  been  absolutely  traced  by  Pflueger  to  the 
nucleoli  of  the  cells  composing  the  salivary  gland  and  the 
pancreas. 

Terminations  of  Motor  Nerve  Fibres. 

In  smooth  muscle,  nerve  fibres  have  been  traced  by 
Frankenhseuser  and  Arnold  into  very  fine  networks,  which, 
connect  together  the  nucleoli  of  the  muscle  fibres. 

The  final  distribution  of  the  nerves  in  striped  muscle  is 
still,  however,  a  question  of  doubt.  It  is  conceded  by  all 
observers  that  the  nerve  fibre,  after  penetration  of  a  muscular 
mass,  splits  into  a  number  of  branches,  that  it  then  loses  its 
medulla,  and  that  a  number  of  nuclei  present  themselves 
upon  the  still  persisting  neurilemma.  These  nuclei,  accumu- 
lated in  mass  as  the  nerve  fibre  approaches  the  muscle 
fibre,  fuse  with  accumulated  nuclei  in  the  sarcolemma  of 


232  COURSE  OF  NERVE  FIBRES. 

muscle  fibre,  to  constitute  a  disk  or  plate  upon  the  surface 
of  the  muscle  fibre.  So  far,  there'  is  general  agreement. 
The  disagreement  concerns  the  ultimate  disposition  of  the 
nerve  fibre.  While  Doyere,  Krause  and  Engelmann  main- 
tain that  the  muscle  plate  is  the  end  of  the  nerve  fibre, 
Kiihne  and  Gerlach  claim  that  the  axis  cylinder  afterwards 
leaves  the  muscle  plate  and  passes  in  to  make  immediate 
connection  with  the  muscle  protoplasm.  From  among  the 
many  opinions  expressed  by  the  most  competent  observers, 
we  elicit  the  fact  that  the  difference  concerns  the  question 
whether  the  axis  cylinder  touches  the  muscle  fibre  at  one 
point  only,  or  whether  it  absolutely  fuses^with  it  within  its 
sarcolemma.  This  latter  view  is  probably  most  correct ; 
but  the  muscle  may  not  be  regarded  as  the  end  of,  or  attach- 
ment to,  the  nerve,  as  Gerlach  has  advocated  ;  the  true  ex- 
pression of  the  fact  is  that  the  nerve  is  an  offshoot  or  an 
addendum  to  the  muscle. 

Course  of  Nerve  Fibres. 

Except  at  their  final  termination,  nerve  fibres  never 
divide  or  anastomose  (if  we  may  use  such  an  expression  of 
tubes  whose  contents  are  more  or  less  solid)  with  each  other. 
Each  fibre  pursues  a  course,  as  straight  as  may  be,  from  the 
centre  to  the  periphery,  or  vice  versa.  To  this  anatomical 
fact  is  due  the  precise  circumscription  or  localisation  of 
sensation  or  motion.  A  motor  nerve  fibre,  irritated  any- 
where in  its  course,  produces  spasmodic  contraction  in  the 
muscle  or  part  of  muscle  to  which  it  is  distributed,  and  no- 
where else.  So  irritation  of  a  sensitive  nerve,  in  any  part 
of  its  course,  causes  sensation  to  be  perceived  at,  or  referred 
to,  the  peripheral  distribution  of  the  nerve,  and  nowhere 
else.  A  blow  received  upon  the  ulnar  nerve  at  the  elbow, 
for  instance,  is  felt  as  a  tingling  sensation  in  both  sides  of 
the  little  finger  and  the  little  finger  side  of  the  ring  finger, 


COURSE  OF  NERVE  FIBRES.  233 

[surfaces  receiving  the  entire  peripheral  distribution  of  this 
nerve.  So  a  tumor  or  foreign  body  pressing  upon  the  intra- 
cranial trunk  of  the  fifth  pair  of  nerves,  may  be  the  cause 
of  the  intense  pain  of  tic-douloureux  experienced  in  the  face. 
Romberg  reports  a  most  instructive  case  illustrative  of  this 
point.  It  was  a  case  in  which  the  patient  had  suffered  for  years 
previous  to  his  death  from  most  distressing  and  frequent 
paroxysms  of  facial  neuralgia,  the  cause  of  which,  as  re- 
vealed on  post-mortem  examination,  was  an  aneurismal  en- 
largement of  the  carotid  artery,  which  made  direct  pressure 
upon  the  fifth  nerve  in  the  vicinity  of  the  Casserian 
ganglion.  The  aneurism  had  surmounted  the  process  of 
bone  on  the  lateral  aspect  of  the  body  of  the  sphenoid, 
which  process  Hilton  has  signalised  and  denominated  the 
"carotid  process,"  having  to  exercise  "the  important  func- 
tion of  preventing  the  artery,  during  its  pulsations,  from 
pressing  on  the  second  division  of  the  fifth — a  nerve  en- 
dowed with  such  exquisite  sensibility,  that  the  slightest 
injury  or  pressure  would  lead  to  the  production  of  serious 
pain  and  distress." 

So  definitely  and.  distinctly  are  sensations  referred  to  the 
periphery  of  nerves,  that  individuals  who  have  suffered 
amputation  wTill  imagine,  on  experiencing  irritation  in  the 
stump,  the  presence  of  the  foot  or  hand,  and  cases  are 
recorded  in  which  patients  have  thus  injured  the  parts  in 
the  attempt  to  step  upon  an  ununited  stump  of  the  leg. 
This  distressing  feeling,  or  imagination  of  feeling,  in  absent 
fingers  or  toes  is,  as  a  rule,  gradually  corrected  by  educa- 
tion or  habit,  but  it  has  persisted  in  some  cases  for  15-20 
years.  It  is  also  because  of  this  distinct  localisation  of  sen- 
sation, that  individuals  who  have  undergone  plastic  opera- 
tions, as  in  the  transplantation  of  skin  from  the  forehead 
for  the  creation  of  a  nose,  still  refer  impressions  received 
upon  the  nose  to  the  forehead.    Of  course,  this  reference 

20 


234  IDENTITY   OF   NERVE   FIBRES. 

only  applies  to  cases  in  which  cutaneous  continuity  has 
been  maintained,  as  in  the  stem  of  the  graft  which  is  twisted 
upon  itself,  not  dissevered,  to  become  the  root  of  the  nose. 
The  facetious  comment  of  Hudibras,  therefore,  regarding 
absolute  ablation  of  skin  and  transplantation  at  distant 
points,  finds  no  foundation  in  fact. 

Identity  of  Nerve  Fibres. 

The  nerve  fibres  are  thus  so  distinctly  separated  into  con- 
ductors of  motion  and  sensation  as  to  preserve  their  charac- 
teristics throughout  their  course.  Nevertheless,  there  is  no 
anatomical  or  chemical  difference  between  motor  and  sensi- 
tive nerves.  It  is-  the  connection  of  a  nerve  fibre,  and  not 
its  construction,  which  determines  its  use.  A  nerve  con- 
nected with  a  muscle  is  a  motor  nerve ;  a  nerve  connected 
with  a  gland  is  a  secretory  nerve ;  a  nerve  connected  with  a 
sensitive  surface  is  a  sensitive  nerve.  So  the  nerves  are 
compared  to  battery  wires  which  may  conduct  force  to  ring 
a  bell,  show  a  light,  or  write  a  message,  according  to  the  con- 
struction of  the  end  apparatus.  Experiments  have  been 
made  to  exhibit  this  indifference  of  the  nerve  fibre,  so  to 
speak,  by  transferring  the  cut  end  of  a  motor  fibre  to  the 
cut  end  of  a  sensitive  fibre,  and  securing  or  awaiting  union 
of  the  apposed  ends.  Philipeaux  and  Vulpian  thus 
observed  after  union  of  the  lingual  (sensitive)  and  hypo- 
glossal (motor)  nerves  of  the  tongue,  that  irritation  of 
the  lingual  produced  contraction  in  the  tongue.  It  is  only 
fair  to  state,  however,  that  the  results  of  later  experiments 
by  Vulpian  have  left  this  question  somewhat  in  doubt. 
For  Vulpian  observed  that  contraction  of  the  tongue 
supervened  upon  irritation  of  the  lingual,  thus  united  to  the 
hypoglossal,  only  when  the  chorda  tympani  fibres  in  the 
lingual  remained  intact.  When  the  chorda  tympani  was 
divided,  the  contractions  did  not  supervene.     These  experi- 


THE  CHEMISTRY   OF   NERVE  TISSUE.  235 

ments,  therefore,  simply  prove  that  motor  nerves  will  con- 
duct for  each  other. 

Indifference  of  Direction  of  Nerve  Force. 

It  is,  however,  a  clearly  established  fact  that  nerve  fibres 
will  conduct  just  the  same  in  both  directions.  That  is,  if 
a  nerve  fibre  be  exsected  and  reversed,  so  that  its  peripheral 
end  is  now  central,  nerve  force  will  travel  along  it,  after 
union  of  the  ends,  just  as  before.  This  fact  was  very 
strikingly  demonstrated  by  Paul  Bert,  who  inserted  and 
fastened  the  denuded  tip  of  a  rat's  tail  into  an  incision  over 
the  centre  of  its  back.  After  firm  union  had  been  secured, 
he  separated  the  tail  from  the  rump  of  the  animal  by 
division  of  its  base.  The  positions  of  the  free  and  fastened 
ends  were  now  exactly  the  reverse  of  the  natural  condition. 
At  the  end  of  three  months,  irritation  of  the  end  of  the 
tail  was  evidently  perceived,  and  at  the  end  of  six  months, 
sensation  was  as  distinct  as  before  the  operation.  The  sensi- 
tive nerve  now  conducted  the  impression  in  a  reverse  direc- 
tion. 

The  Chemistry  of  Nerve  Tissue. 

Four-fifths  of  nervous  tissue  is  water,  and  of  the  remain- 
ing fifth,  the  most  essential  element  part  is  the  peculiar 
albumenoid  substance,  known  as  lecithine,  which  is  remark- 
able for  the  amount  of  phosphorus  which  it  contains. 
Lecithin  is  a  nitrogenous,  organic,  phosphorised  acid, 
a  glycerinphosphoricacid,  which  is  made  up  of  radical  fatty 
acids  (stearic,  oleic,  etc.,  acids),  and  a  derivative  of 
ammonia  (neurine).  Lecithin  and  cerebrin,  an  additional 
albumenoid  body  of  somewhat  similar  constitution  (but 
more  easily  soluble  in  alcohol  and  less  easily  in  ether),  give 
to  nerve  tissue  its  physical  characteristics.  Both  these  sub- 
stances swell  in  water,  and  thus  form  the  drops  of  medullary 


236         ACTION  OF  ELECTRICITY  UPON  NERVE  TISSUE. 

tissue  which  exude  from  the  nerve  on  microscopic  examina- 
tion. Both  these  substances  more  nearly  resemble  casein 
(in  easy  solubility  in  dilute  acids  and  solutions  of  soda)  than 
any  other  familiar  albumenoid  body.  The  predominance  of 
phosphorus  also  makes  itself  manifest  in  the  mineral  salts 
entering  into  the  composition  of  nerve  tissue.  The  analyses 
of  Bibra  show  that  of  100  parts  of  mineral  matter  from  the 
human  brain,  the  phosphates  of  potassium,  sodium,  iron, 
lime  and  magnesium  form  84.5  parts.  This  presence  of 
phosphorus,  in  such  quantities,  in  all  parts  of  nervous 
matter,  is  the  fact  of  highest  interest  from  a  chemical 
point  of  view. 

That  chemical  processes  are  continually  at  work  in  living 
nerves  is  proven  by  the  existence  of  electric  currents  in  the 
nerves.  In  the  absence  of  any  other  cause,  electricity  cannot 
exist,  or  be  developed,  without  chemical  action.  The  fact,  too, 
that  nerve  fibres  degenerate  so  soon  as  they  are  separated 
from  their  central  connections,  also  proves  the  presence  of 
chemical  action.  We  may  surmise  that  the  chemical  pro- 
cesses in  nerve  fibres  consist  essei  tially  in  oxidation  of  the 
non-nitrogenous  elements  of  the  blood,  whose  chief  product 
is  carbonic  acid  gas,  but  we  have  as  yet  no  positive  and 
definite  knowledge  concerning  the  fuel  of  nerve  tissue. 

The  Action  of  Electricity  upon  Nerve  Tissue. 

Nerve  fibre  differs  from  muscle  in  not  manifesting  the 
action  of  stimulants  or  irritants  in  any  visible  effects. 
Nerve  fibre  does  not  shrink,  contract,  or  undergo,  under  irri- 
tation, any  perceptible  change.  Nerve  fibre  exhibits  its 
susceptibility  to  irritants  only  in  the  effects  produced  in  the 
structures  innervated;  that  is,  in  the  contraction  of  muscle, 
secretion  of  glands,  perceptions  of  impressions  of  general  or 
special  sense,  or  manifestations  of  the  intellect.  Neverthe- 
less, a  nerve  fibre  is  affected  by  the  passage  along  its  course 


NERVE   FORCE.  237 

of  the  electric  current.  When  the  constant  current  of 
electricity  is  brought  to  bear  upon  a  nerve,  the  whole  nerve 
is  brought  to  a  condition  of  electric  tension,  the  so-called 
electrotonus,  during  the  existence  of  which,  the  sensitive- 
ness of  the  nerve  is  very  curiously  changed.  For  in  the 
part  of  the  nerve  near  the  positive  pole  the  sensitiveness  to 
irritation  and  the  rate  of  conduction  are  markedly  lessened, 
while  in  the  part  of  the  nerve  near  the  negative  pole  the 
sensitiveness  to  irritation  and  the  rate  of  conduction  are  as 
markedly  increased.  The  condition  of  the  nerve  at  the 
region  of  diminished  sensitiveness  is  known  as  anelectrotonus, 
while  the  condition  at  the  region  of  increased  sensitiveness 
is  known  as  catelectrotonus.  These  regions,  however,  are 
not  confined  to  the  intrapolar  spaces,  but  extend  on  either 
side  beyond  the  poles  throughout  the  entire  course  of  the 
nerve.  Between  the  poles  is  a  point  where  neither  increase 
nor  decrease  may  be  observed  and  this  point  is  known  as 
the  neutral  point.  Finally,  the  arrest  or  diminution  of  the 
natural  electric  current,  caused  by  the  passage  of  the  natural 
nerve  force,  constitutes  what  is  known  as  the  negative 
variation  of  the  electric  current. 

Nerve  Force. 

"We  are  as  ignorant  of  the  ultimate  changes  in  nerve  cells, 
which  attend  the  conversion  of  latent  force  in  the  blood 
into  active  nerve  force,  as  of  the  ultimate  changes  which 
take  place  in  any  body,  when  it  produces  light,  heat, 
electricity,  or  any  physical  force.  We  are  forced  to  content 
ourselves,  therefore,  with  the  study  of  the  properties  and 
actions  of  nerve  or  other  force.  We  recognise  the  fact  that 
the  influence  of  irritants  or  impressions  are  conducted  along 
afferent  nerve  fibres  to  nerve  cells,  whence  they  are  trans- 
mitted through  efferent  nerves  to  motor,  glandular,  etc., 
structures.      Such    a  process  constitutes  a  reflex  action. 


238  REFLEX   AXD   VOLITIONAL  ACTION. 

But  the  nerve  cell  has  also  the  property  of  retaining  the  in- 
fluence of  the  external  impression,  and  releasing  it  at  a  later 
period.  This  later  period  may  be  very  remote  from  that  of 
the  original  impression.  When  the  action  then  supervenes, 
it  is  known  as  a  volitional  act.  Acts  of  volition  therefore 
are,  in  reality,  reflex  actions,  whose  constituents  are 
separated  by  longer  intervals. 

We  do  not,  of  course,  look  upon  nerve  force  as  a  simple 
transfer  of  the  external  irritant.  The  nerve  force  is  just  as 
different  from  the  external  force,  as  muscular  force  is  from 
nerve  force.  And  just  as  a  small  amount  of  nerve  force 
may  call  into  action  a  large  amount  of  muscular  force,  so 
a  small  amount  of  external  force  may  evoke  a  large  amount 
of  nerve  force.  The  nervous  system  is,  thus,  just  as  much  a 
machine  as  is  the  muscular  system,  or  the  gland  system. 
The  nervous  system  is  a  machine  for  the  transformation  of 
outside  force  into  nerve  force.  We  can,  therefore,  no  more 
conceive  of  force  being  developed  spontaneously,  or 
automatically,  in  the  case  of  nerves,,  than  in  the  case  of 
muscles.  What  is  true,  thus,  of  the  grosser  phenomena  of 
nerve  tissue,  sensation,  motion,  secretion,  etc.,  must  be  true 
of  the  more  intricate  processes  connected  with  the  special 
senses,  and  the  faculties  of  the  mind.  Impressions  are 
made  upon  the  nerve  cells  through  the  avenues  of  nerve 
fibres  of  general  or  special  sense.  These  impressions  may 
be  reflected  to  act  at  once  through  motor  nerves,  or  they 
may  be  stored  up  to  constitute  memory.  We  do  not  know 
what  material  changes  occur  in  the  nerve  cells  during  the 
reception,  reflection  or  retention  of  these  impressions,  any 
more  than  we  know  what  changes  take  place  in  any  proto- 
plasm when  it  absorbs,  assimilates,  or  excretes  matter,  or  any 
more  than  we  know  what  changes  take  place  in  an  iron  bar 
when  it  becomes  magnetic.  We  appeal  in  our  ignorance  to 
molecular  changes,  but  we  do  not  accept  them  as  positive 


KEFLEX  AND  VOLITIONAL  ACTION.  239 

facts  until  their  character  and    degree  shall  have  been 
definitely  demonstrated. 

What  shall  we  say  then  of  the  higher  actions  of  the  nerve 
cells  (cerebrum),  which  have  come  to  be  differentiated 
from  the  rest  and  set  apart  for  purely  intellectual  pur- 
pose? 

We  observe,  in  the  first  place,  that  the  development  of 
these  cells  is  a  gradual  process.  The  cerebrum  is  an 
addition  to  forms  of  life  highest  in  the  animal  scale.  Its 
cells  are  intimately  linked  with  the  cells  of  all  other 
ganglionic  masses  lower  in  physiological  dignity.  We  should 
therefore  naturally  infer  that  the  same  laws  which  apply  to 
the  nerve  fibres  and  cells  composing  the  spinal  cord  and 
sympathetic  system  would  also  apply  to  the  nerve  fibres  and 
cells  of  the  cerebrum.  We  observe,  then,  in  the  second  place, 
that  no  intellectual  phenomena  of  any  kind  are  born  with 
an  individual  of  even  the  very  highest  form  of  life  in  the 
animal  scale.  All  the  movements  and  actions  of  the  body 
are  as  distinctly  reflex  in  the  new  born  child  as  in  the  foetus 
in  utero.  The  cry,  the  seizure  of  the  breast,  the  direction 
of  the  eyes  towards  a  light,  are  all  purely  and  simply  reflex 
actions.  The  intellectual  manifestations  are  in  every  case 
slowly,  and  we  might  almost  say  painfully,  acquired.  The 
capacity  or  aptitude  for  acquisition  exists,  it  is  true,  because 
the  character  of  the  apparatus  is  rigidly  determined  by 
inheritance,  but  the  acquisition  itself  is  entirely  a  matter 
of  education.  A  human  being  kept  away  from  light,  would 
not  be  able  to  see ;  kept  from  sound,  it  could  not  hear  or 
speak ;  kept  from  the  reception  of  ideas,  it  could  not  think. 
We  find  ourselves  forced  to  the  conclusion  that  the  purely 
intellectual  processes,  as  they  are  called,  the  memory,  the 
reason,  the  will,  result  entirely  from  the  impression  of 
outside  influences.  Inheritance  determines  the  aptitude 
or  plasticity  of    the   brain   cells   to   impressions,  and  the 


240  THE  RATE  OF  CONDUCTION. 

character  of  the  impressions  determines  the  character  of 
the  mind.     In  other  words : — 

•'L'instruction  fait  tout ;  et  les  mains  de  nos  peres 
Grave  en  nos  faible  cceurs  ces  premieres  characteres" 
Que  l'example  et  le  temps  nous  viennent  retracer 
Et  que  peut-etre  en  nous  Dieu  seul  peut  effacer."        Voltaire. 

(Instruction  does  all  ;    our  father's  hands 
Engrave  in  our  hearts  indelible  bands, 
Which  time  and  example  only  retrace 
And  which  God  [death]  alone  may  ever  efface.) 

Hate  of  Conduction. 

Although  we  are  ignorant  of  the  ultimate  essence  of  nerve 
force  we  are  by  no  means  entirely  unacquainted  with  its 
properties  and  effects.  We  have  in  the  first  place  some 
quite  definite  information  as  to  the  velocity  or  rapidity 
with  which  it  travels.  When  this  question  first  excited 
the  attention  of  physiologists,  it  was  considered  a  subject 
beyond  the  possibilities  of  human  comprehension.  Haller 
thought  that  it  would  be  impossible  to  measure  the  rate  of 
conduction  of  nerve  force  because  there  was  not  sufficient 
distance  for  estimate  as  in  the  case  of  light.  But  as  Goethe 
has  said  "one  must  continue  to  believe  the  inconceivable  to 
be  conceivable,  else  there  will  be  no  discovery."  Continued 
investigation  has  at  last  been  rewarded  with  positive  results 
so  that  we  possess  now  tolerably  accurate  data  regarding 
the  velocity  of  nerve  force.  By  attaching  two  levers  to  two 
different  parts  of  a  muscle  and  causing  the  muscle  to 
contract  by  stimulating  successively  two  different  parts  of 
the  trunk  of  the  nerve  terminating  in  the  muscle,  Marey 
wras  able  to  determine  that  the  response  of  the  muscle  was 
quicker  to  the  irritation  nearer  the  muscle.  The  interval 
which  lapsed  between  response  to  stimulus  at  different 
points  along  the  nerve  corresponds  to  the  rate  of  conduction 
between   the  points.    The  distance  between   these  points 


NERVE  FORCE  AND  ELECTRICITY.  241 

being  known,  it  is  easy  to  estimate  the  rate  of  conduction 
along  the  entire  nerve.  In  like  manner,  by  noting  the 
interval  of  time  which  lapses  between  perception  of  an 
irritation  at  a  distant  point,  as  at  the  foot,  and  at  a  near 
point,  as  on  the  face,  the  rate  of  conduction  along  sensitive 
nerves  was  approximately  established.  Though  this  rate 
of  conduction  differs  in  different  animals,  being  more  rapid 
in  warm  blooded  animals;  differs  in  the  same  animal  at 
different  degrees  of  temperature,  being  increased  by  heat 
and  diminished  by  cold ;  differs  also  in  the  same  nerve  at 
different  parts  of  it  course,  being  increasing  in  motor  nerves 
as  the  nerve  approaches  the  periphery,  and  in  sensitive 
nerve  as  it  approaches  the  centre  ;  differs,  lastly,  according 
to  the  degree  of  freshness  or  fatigue,  being  much  slower  in 
fatigue ;  the  general  velocity  of  conduction  is  estimated  at 
about  100  feet  per  second.  Auerbach  and  v.  Kries  have 
shown  that  the  perception  of  the  difference  between  two 
different  impressions  upon  the  sense  of  touch  requires,  as  a 
rule,  0.021-0.036  of  a  second  ;  of  hearing  0.019-0.053  second, 
according  to  the  quality  of  the  tone  ;  but  the  localisation  of 
a  noise  required  0.032-0.077  second.  The  perception  of  the 
difference  of  two  objects  addressed  to  the  sense  of  sight 
required  0.011-0.017  second.  The  recognition  of  the  differ- 
ence between  two  different  colors  (blue  and  red)  required 
0.012-0.034  second.  In  appeals  to  the  sense  of  touch  and 
taste  in  the  tongue,  Yintschgau  and  Honigsmied  found  that 
touch  was  always  experienced  first.  The  perception  of  taste 
required  for  salt  0.05,  for  sugar  0.20,  for  quinine  0.49 
second. 

Nerve  Force  Analogous  to,  but  not  Identical  with,  Electricity. 

Though  electricity  more  closely  than  any  other  force  re- 
sembles nerve  force,  their  rates  of  travel  alone  afford  positive 
evidence  that  nerve  force  is  not  electricity.    For  electricity 

21 


242         RECEPTION  AND  PERCEPTION  OF  IMPRESSIONS. 

travels  at  the  rate  of  many  thousand  miles  a  second.  While 
it  is  true  that  electricity  is  developed  in  nerves  during  rest 
of  the  nerve,  as  the  result  of  the  chemical  operations  in 
continuous  operation,  this  electricity  is  at  once  arrested  so 
soon  as  the  chemical  force  may  expend  itself  as  nerve  force. 
That  is,  the  most  delicate  galvanometer  fails  to  register  in 
nerves  the  faintest  electrical  current  during  the  transmission 
of  nerve  force.  This  fact  is,  of  course,  simply  another 
illustration  of  the  operation  of  the  law  of  the  conservation 
of  force. 

Comparative  Velocity  of  Nerve  and  other  Forms  of  Force. 

Nerve  force,  thus,  travels  at  about  the  rate  of  an  express 
train.  It  is  much  more  rapid  than  muscle  force,  but  is 
infinitely  more  slow  than  light  or  electricity.  We  may  form 
some  more  definite  idea  of  the  velocity  of  nerve  force  by  a 
comparison  with  that  of  some  more  familiar  forces.  Le  Bon 
presents  us  for  this  purpose  the  following  table  in  which  the 
figures  represent  so  many  metres  (a  metre  is  about  40  inches) 
per  second : — 

Muscular  Contraction    -  1 

Race  Horse         -----  26 

Locomotive    -  -  27 

Nerve  Force 30 

Eagle's  Flight 35 

Sound  in  Air      -----  332 

Cannon  Ball 550 

Earth's  Revolution  about  the  Sun     -  30,800 

Light 300,000,000 

Electricity  -        -        -  -    464,000,000 

The  Reception  and  Perception  of  Impressions. 

We  fail  to  appreciate  the  interval  of  time  between  the 
reception  and  perception  of  an  impression  simply  because  of 


RECEPTION  AND  PERCEPTION  OF  IMPRESSIONS.         243 

the  short  distance  to  be  traversed  between  the  brain  and 
the  ends  of  the  most  distant  nerves.  In  very  large  animals, 
that  is,  in  animals  with  very  long  nerves,  as  in  the  whale,  a 
harpoon,  thrust  into  the  body  near  the  tail,  is  not  felt  for  an 
entire  second,  and  as  an  additional  second  must  elapse  before 
responding  motor  force  can  be  sent  down  from  the  brain, 
the  movement  of  the  animal  could  not  occur  in  less  than 
two  seconds.  So,  in  the  case  of  a  tall  man,  a  mosquito 
operating  upon  the  foot,  would  have  the  one-sixth  of  a  second 
to  make  its  escape,  ample  time,  as  we  have  seen,  for  the 
quick  movements  of  insect  life.  Mr.  Flower  has  expressed 
the  opinion  that  the  large  animals  of  the  tertiary  epoch  were 
all  slow  of  motion  and  stupid,  in  comparison  with  modern 
species,  and  this  sluggishness  and  dulness  finds  explanation 
in  the  mere  size  of  the  animals  and  corresponding  length 
of  the  nerves.  So  the  proverbial  obtuseness  and  imper- 
turbability of  giants  stands  in  marked  contrast  to  the  acute- 
ness  and  activity  of  small  people.  Ponies  and  terriers  are 
much  more  active  and  vivacious  than  horses  and  mastiffs. 

But  we  are  not  to  forget  that  the  character  of  the  receiv- 
ing and  generating  centres  is  also  an  important  factor  in 
this  consideration.  Thus  children  "lose  the  benefit  of  their 
small  stature  from  want  of  command  and  correlation  of 
their  faculties,"  that  is,  from  want  of  development  of  the 
nerve  cells.  Cold  blooded  feel  much  less  acutely  than 
warm  blooded  animals.  In  Chamber's  Journal  is  the  story 
of  a  shark  caught  with  a  line,  the  hook  of  which  tore  open 
the  abdominal  cavity,  cut  out  the  liver,  and  left  the  intes- 
tines hanging  from  the  body.  The  sailors,  in  abhorrence, 
threw  it  into  the  sea,  but  it  continued  near  the  boat  and 
shortly  afterwards  pursued  and  attempted  to  devour  a 
mackerel.  In  one  of  the  older  numbers  of  The  Clinic  is  a 
well  authenticated  statement  to  the  same  effect.  A  fish 
was  caught  in  the  eye  by  a  hook,  and  the  eye  ball  was  torn 


244  THE  ANCIENT  SIGNIFICANCE  OF  NEHVES. 

from  the  socket.     The  eye  ball  was  then  left  upon  the  hook 
as  a  bait,  and  in  a  little  while  it  secured  the  rest  of  the 
animal  in  the  usual  way. 
It  is  therefore  not  true  that 

"The  poor  beetle  that  we  tread  upon 
In  corporal  sufferance  finds  a  pang  as  great 
As  when  a  giant  dies." 

though  the  pain  experienced  by  the  albatross,  shot  by  the 
ancient  mariner,  may  have  been  as  keen  as  that  felt  by 
a  human  being.  The  sportsman,  who  so  cruelly  wounds 
birds  and  runs  down  mammals,  inflicts  far  more  torture 
than  the  physiologist  with  his  experiments  upon  frogs,  and 
has  less  justification  for  his  work. 

Ancient  Significance  of  Nerves. 

Nerves  were  not  known  as  such  by  the  older  anatomists 
and  physiologists.  Hippocrates  always  confounded  nerves 
and  tendons.  Hence  the  derivation  of  the  word  nerve 
(vr.vpov,  cord).  We  speak  yet  of  a  strong  nervous  man,  with 
reference  to  the  original  meaning  of  the  term,  and  a  weak 
nervous  woman,  with  reference  to  its  modern  significance. 
Although  the  true  nature  of  nerves  was  known  to  Erasis- 
tratus  and  Galen,  we  do  not  find  any  general  recognition  of 
it  until  almost  within  our  own  times.  All  the  allusions  of 
Shakespere  concerning  nerves,  evidently  refer  to  the  sinews 
or  tendons.    Thus  Macbeth  cries  out  to  the  ghost: — 

"Take  any  shape  but  that,  and  my  firm   nerves 
Shall  never  tremble." 

And  Hamlet  says,  alluding  to  bloodvessels  as  cords: — 

"As  hardy  as  the  Nemean  lion's  nerve." 

The  French  translate  the  "sinews  of  war"  literally,  "ks  nerfs 
de  la  guerre" 


THE  EFFECTS  OF  USE  AND  DISUSE.  245 

The  Effects  of  Use  and  Disuse. 

The  literary  allusions  to  the  nervous  system,  therefore, 
still  have  reference  to  the  mind  and  the  mental  faculties, 
chiefly  from  a  metaphysical  point  of  view,  as  sufficient 
time  has  scarcely  yet  elapsed  for  general  appreciation  of 
the  physicial  significance  of  nervous  tissue.  But  there  is 
one  point  connected  with  this  tissue  which  has  not,  in  its 
effects,  at  least,  escaped  general  recognition.  And  that  is, 
that  the  tone  of  the  nervous  tissue  is  only  maintained  and 
sustained  by  its  exercise.  If  a  nerve  of  whatever  character 
be  cut,  and  union  of  the  divided  ends  be  prevented,  atrophy 
of  the  nerve  inevitably  ensues.  The  essential  element  of 
the  nerve  undergoes  a  granulo-fatty  degeneration  and  at 
last  entirely  loses  its  capacity  to  conduct  force.  This  atrophy 
then  not  only  affects  the  nerve,  but  also  the  end  apparatus 
of  the  nerve.  The  structure  innervated  dies  with  the  nerve. 
Nor  is  the  field  of  destruction  limited  to  the  nerve  and  its 
distribution ;  the  nerve  centres  also  suffer  atrophy  and 
finally  cease  to  functionate  at  all.  The  same  effect  follows 
disuse  of  the  centre,  even  though  anatomical  integrity  of 
structure  be  preserved.  The  brain  develops  by  use  and 
atrophies  by  disuse.  No  sight  is  more  melancholy  than 
that  gradual  contraction  of  ideas,  that  irritability  to  trival 
cause,  which  inevitably  supervenes  in  an  active  and  liberal 
mind  when  its  faculties  cease  to  be  exercised.  Middle  aged 
men  who  retire  from  active  pursuits  to  secure  the  otium  cum 
dignitate,  secure  the  dignity  perhaps,  but  generally  lose  the 
ease.  Some  allowance  must,  of  course,  be  made  for  the 
defective  nutrition  of  advancing  age,  but  aside  from  this 
factor,  or  superadded  to  it,  is  the  more  marked  desolation 
effected  by  atrophy  from  disuse.  There  are  forms  of  animal 
life  which  in  the  earlier  phases  of  existence  are  endowed 
with  motion  (cilia)  and  various  organs  of  special  sense.     No 


246  THE  EFFECTS  OF  USE  AND  DISUSE. 

sooner,  however,  do  they  become  fixed  in  a  convenient  place 
than  they  lose  their  microscopic  oars,  lose,  one  after  another, 
their  special  senses,-  become  thus  reduced  to  shapeless,  inert, 
masses  of  protoplasm,  and  thus  vegetate  simply  for  the  rest 
of  their  existence.  Such  reduction  and  waste  occurs  as  the 
result  of  disuse  throughout  the  animal  scale. 

Wo  realise  thus  the  force  of  Schiller's  observation  to 
Korner;  ilDie  Hauptsache  ist  der  Fleisz;  clenn  dleser  giebt 
iiicht  nur  die  Mlttel  des  Lebens,  sondern  er  giebt  ihm  auch 
seinen  alleinigen  Werth."  (The  chief  thing  is  industry ;  it 
not  only  furnishes  the  means  of  living,  but  also  gives  to 
life  its  sole  worth). 

The  atrophic  changes  in  the  nervous  tissue  incident 
to  age,  make  themselves  manifest  in  the  action  of  the  nerve 
centres  as  well  as  in  the  loss  of  conductivity  in  the  nerve 
fibres.  The  intellectual  and  moral  faculties  suffer  the  same 
alterations  as  the  special  senses.  The  organs  of  communica- 
tion with  the  external  world  being  blunted  in  their  nice 
perceptions,  the  old  man  has  only  his  memories  whence  to 
derive  his  intellectual  food.  As  he  cannot  comprehend  the 
world  about  him  in  its  new  order,  he  looks  upon  all  that  is 
new  with  distrust,  if  not  absolute  aversion.  But  this, 
blunting  of  the  sympathies  enables  age  to  regard  events  and 
occurrences  dispassionately,  and  hence  peculiar  wisdom  is 
ascribed  to  this  period  of  life  by  all  peoples  and  in  all  lands, 
"If  we  consider  this  epoch,"  remarks  Carl  Vogt,  one  of  the 
most  profound  philosophers  of  his  day,  "in  its  retrocessions 
of  the  feelings,  in  its  insensibility  to  external  impressions, 
in  its  lack  of  the  loftier  inspirations,  in  its  insipidity  of 
intellectual  productions,  we  may  well  cease  to  begrudge  it, 
the  wisdom  usually  ascribed  to  it." 

At  last,  ensues  the  last  stage  of  atrophy,  and  : — 

"From  Marlborough's  eyes  the  tears  of  dotage  flow 
And  Swift  expires  a  driveler  and  a  show." 


THE   BLOOD   AND  ITS  PROPERTIES.  247 


LECTURE    XII. 
THE  BLOOD  AND  ITS  PKOPERTIES. 

CONTENTS. 

The  Value  of  the  Blood— The  Transfusion  of  Blood— The  Constitu- 
tion of  the  Blood — The  Color  of  the  Blood — Reaction  of  the  Blood 
—The  Odor  of  the  Blood— The  Taste  of  the  Blood— The  Temperature 
of  the  Blood— The  Weight  of  the  Blood— The  Quantity  of  the  Blood 
— The  Morphology  of  the  Blood — The  Red  Blood  Corpuscles — Size 
of  the  Red  Corpuscles — Number  of  the  Red  Corpuscles — Elasticity 
of  the  Red  Corpuscle — Constitution  of  the  Red  Corpuscles — Use  of 
the  Red  Corpuscles — The  Colorless  Blood  Corpuscles— The  Blood 
Plasma— The  Coagulation  of  the  Blood— The  Blood  as  the  Substitute 
of  the  Body. 

The  Value  of  the  Blood. 

The  blood  is  for  the  most  part,  the  prepared,  digested, 
fluidified,  food.  Bub  the  blood  is  made  up  also  of  the 
waste  products  of  the  body.  The  blood  thus  officiates  as 
the  fresh  food  (solid,  liquid,  and  gaseous)  supply  and  at  the 
same  time,  as  the  sewage  escape.  No  where  in  art  may  we 
observe  a  nutrient  supply  conveyed  along  the  same  conduits 
or  tubes  with  waste  matter  without  suffering  contamination. 
"The  blood  circulating  through  the  body  may  be  regarded 
as  a  river  flowing  by  numerous  canals  through  a  populous 
city,  which  not  only  supplies  the  wants  of  the  inhabitants, 
but  conveys  from  them,  all  the  impurities  which  through 
various  channels  find  their  way  into  its  stream"  (Bennet). 

The  mass  of  the  blood  is  the  digested  food.  To  secure 
the  elaboration  of  the  coarse  elements  of  the  food  into  the 
finished  elements  of  the  blood,  is  the  work  of  a  digestive 
apparatus,  which  is  extensive  and  complicated  according  to 
the  nature  of  the  food.    For  food  is  of  no  use  to  the  body 


248  THE  TRANSFUSION  OF  BLOOD. 

until  it  is  converted  into  blood.  It  is  the  blood  which  is 
consumed  in  the  processes  of  life  ;  thus  directly  or  indirectly, 
all  animals  are  carnivorous. 

The  blood  of  plants  is  the  sap  which  is  made  up  of  the 
fluidified  salts  of  the  earth.  The  material  which  acts  as 
blood  for  the  lowest  forms  of  animal  life  is  the  sea  or  the 
water  in  which  they  live. 

Blood  (Saxon,  blod),  in  some  form  or  other,  is  thus  the 
most  important  juice  in  the  body,  and  its  value  was  recog- 
nised long  before  its  nature  and  character  were  established. 
We  observe  something  of  the  popular  recognition  of  its 
significance  in  the  aversion,  or  feeling  of  horror,  which 
the  mere  sight  of  it  occasions.  The  shedding  of  blood 
is  associated  with  the  loss  of  life.  So  blood  is  the  fluid, 
so  to  speak,  with  which  tragic  artists  paint.  Helena,  when 
she  finds  Lysander  asleep  (Midsummer  Nights  Dream),  can 
not  believe  him  hurt,  because  as  she  says : — 

"I  see  no  blood,  no  wound!" 

And  the  watchman  in  the  grave  yard  scene  (Romeo  and 
Juliet)  appreciates  the  injury  to  life  with  the  exclamation 
and  injunction: — 

"The  ground  is  bloody;    search  about  the  church  yard: 
Go,  some  of  you,  whoe'er  you  find,  attach." 

The  Transfusion  of  Blood. 

Perhaps  no  single  experiment  so  convincingly  exhibits 
the  fact  that  "the  blood  is  the  life"  as  the  practice  of  inject- 
ing fresh  healthy  blood  into  the  veins  of  an  animal  dying 
from  its  loss.  Almost  simultaneously  with  the  reception 
of  the  blood,  the  respiration  becomes  more  profound,  the 
pulse  becomes  again  perceptible,  consciousness  returns 
with  motion  and  sensation,  in  short,  the  animal  is  restored 
to  life. 


TIIE  TRANSFUSION"  OF  BLOOD.  249 

The  operation  of  transfusion  of  blood  was  first  practised 
on  man  by  a  French  physician,  Denis,  June  15,  1667, 
with  defibrinated  blood  from  a  calf,  though  numerous 
experiments  had  been  previously  made  upon  lower  animals. 
The  first  recorded  inti%ition  of  the  operation  is  found  in 
Ovid's  Metamorphoses,  book  vii,  fable  ii,  in  the  order  of 
Medea  to  the  daughters  of  Pelos :  "unsheath  your  swords, 
and  exhaust  the  ancient  gore,  that  I  may  replenish  his 
empty  veins  with  youthful  blood."  But  this  statement  is 
usually  construed  by  commentators  to  have  only  meta- 
phorical meaning,  and  to  have  reference  to  the  vivifying  effect 
of  a  potent  decoction  which  Medea  had  previously  used  on 
animals  and  men.  However  this  may  be,  it  is  known  that 
the  modern  operation  of  transfusion  was  largely  discussed 
by  the  metaphysicians  of  the  middle  ages,  that  period 
so  replete^  with  curious  and  fantastic  projects,  and  was  even 
practised  to  some  extent  upon  lower  animals.  As  a  sample 
of  the  fabulous  expectations  entertained  of  transfusion,  at 
this  time,  I  may  mention  that  it  was  generally  believed 
that  the  long  sought  secret  of  rejuvenation  had  been  at  last 
discovered.  Very  soon  after  the  first  practice  of  the  opera- 
tion upon  man,  marvelous  results  began  to  be  reported. 
Cases  of  insanity  were  cured,  lost  special  senses  were  restored, 
and  aged  and  decrepit  constitutions  rehabilitated  with  the 
vigor  of  youth.  Time,  the  experimentum  cruets  of  all  dis- 
coveries, soon  dissipated  all  these  conceits,  and  the  number 
of  accidents  and  fatal  results  which  attended  the  operation 
at  last  brought  it  into  disrepute,  when  legal  injunction  caused 
the  practice  of  it  to  be  suspended  and  forgotten.  In  this 
oblivion  it  laid,  then,  until  the  beginning  of  our  own  century, 
when  it  was  revived  by  a  distinguished  obstetrician  of 
Dublin,  Blundell  (1818),  with  such  improvements  in  method 
and  restriction  in  practice,  as  to  give  it  permanent  place 
among  the  most  valuable  acquisitions  to  modern  therapy. 


230  THE  TRANSFUSION   OF  BLOOD. 

Iii  our  day,  transfusion  is  limited  to  cases  of  hemorrhage, 
where  it  is  peculiarly  adapted  to  meet  the  indications,  and 
to  cases  of  poisoning  by  toxic  agents  (sewer  gases,  for 
instance)  for  which  we  have  no  antidote.  A  temporary 
renewal  or  protraction  of  life  m^-  also  be  effected  with 
it  in  cases  of  phthisis,  and  sometimes  permanent  relief 
afforded  in  cases  of  inanition  from  any  cause,  when  the 
ordinary  avenues  of  food  are  temporarily  blocked,  or  may 
not  be  addressed,  as  in  cases  of  gastric  ulcer.  It  is  highly 
probable,  however,  that  other  nutrient  fluids,  an  artificial 
serum,  or  milk,  will  gradually  substitute  blood  in  the 
majority  of  cases. 

Though  the  transfusion  of  a  few  ounces  of  blood  usually 
suffice,  according  to  the  observations  of  J.  Worm  Muller, 
rabbits  and  dogs  may  receive  as  much  as  eighty  per  cent, 
additional  blood  without  permanent  injury.  Inexplicable 
laws  regulate  the  kind  of  blood  which  an  animal  may  receive. 
The  transfusion  of  the  blood  of  birds  into  the  veins  of  mam- 
mals produces  convulsions  and  death,  as  does  also  the  trans- 
fusion of  some  mammals  blood  into  the  veins  of  other  mam- 
mals. Dogs  blood  may  be  injected  into  the  veins  of  rabbits 
with  perfect  impunity,  while  sheeps  blood  rapidly  proves 
fatal  (Mittler). 

Most  remarkable  results  have  been  obtained  by  the  injec- 
tion of  blood  into  the  veins  of  animals  recently  dead.  Brown- 
Scquard  has  performed  a  great  many  experiments  of  this 
kind,  and  his  accounts  of  effects  secured  would  seem  incredi- 
ble, were  they  not  in  full  accord  with  our  knowledge  of  the 
part  the  blood  plays  in  the  animal  economy.  On  one 
occasion,  he  decapitated  a  dog,  taking  care  to  make  the 
section  below  the  point  where  the  vertebral  arteries  pene- 
trate their  osseous  canals.  "Ten  minutes  after  cessation  of 
the  respiratory  movements  of  the  nafes,  lips  and  lower  jaw, 
I  inserted  into  the  three  arteries  of  the  head  canuke  con- 


THE  CONSTITUTION  OF  TIIE  BLOOD.  251 

nectcd  by  caoutchouc  tubes  to  a  copper  cylinder  contain- 
ing oxygenated  blood.  The  blood  was  now  injected  by 
means  of  a  syringe.  In  two  or  three  minutes,  the  eyes 
began  to  move,  as  also  the  muscles  of  the  face,  and  these 
movements  seemed  directed  by  the  will.  I  prolonged  this 
experiment  a  quarter  of  an  hour,  and  during  all  this  time, 
these  movements,  apparently  voluntary,  continued  to  take 
place.  When  I  ceased  the  injections,  the  movements  ceased 
and  were  soon  replaced  by  convulsive  movements  of  the 
eyes,  face,  respiratory  movements  of  the  nose,  lips  and  jaws, 
and  finally  by  the  tremors  of  the  death  agony.  The 
pupils  now  dilated  and  became  fixed  as  in  ordinary  death." 
On  a  subsequent  occasion,  the  same  experimenter  injected 
into  the  veins  of  a  dog,  just  dead  from  peritonitis,  some 
fresh  blood  from  a  living  dog,  and  the  dead  dog  so  far  re- 
vived, as  to  stand  upon  his  feet,  wag  his  tail,  make  various 
voluntary  movements,  and  survive  for  twelve  and  a  half 
hours,  when  he  again  laid  down,  and  died  the  second  time. 
No  physiologist  has,  as  yet,  had  the  temerity  to  practice 
this  operation  upon  the  brain,  or  the  whole  body,  of  a  human 
being,  not  even  for  juridical  purposes,  where  it  might  seem 
justifiable,  but  there  can,  of  course,  be  no  doubt  as  to  its 
result.  Prof.  Vulpian  remarks  upon  this  subject : — "If  a 
savant  should  attempt  this  experiment  upon  the  head  of  an 
individual  who  had  been  decapitated,  he  would  assist  in  the 
production  of  a  grand  and  terrible  spectacle  ;  he  would 
re-awaken  in  the  head  all  its  cerebral  functions ;  he  wTould 
restore,  in  the  eyes  and  facial  muscles,  the  movements,  which 
in  man  are  evoked  by  the  emotions,  and  the  thoughts,  of 
which  the  brain  is  the  seat." 

Constitution  of  the  Blood. 

The  blood  consists  of  a  fluid,  the  so-called  plasma  (Schultze), 
and  of  formed  elements  suspended  in  the  fluid,  the  so-called 


252  THE  COLOE  OF  THE  BLOOD. 

blood  corpuscles  (Miiller).  The  only  exception  to  this  con- 
stitution of  blood  is  offered  by  certain  worms,  the  nemertinea, 
in  whose  blood  no  corpuscles  have  as  yet  been  dis- 
covered. 

The  Color  of  the  Blood, 

The  blood  of  all  vertebrate  animals,  with  the  single  ex- 
ception of  the  lowest  of  all,  the  lancelet,  is  red.  The  blood 
of  invertebrate  animals  is  either  colorless,  or  is  of  other  color 
than  red,  as  blue,  yellow,  green,  brown,  etc.  When  the 
blood  of  invertebrate  animals  is  colored,  it  is  the  plasma 
which  contain  the  coloring  matter,  whereas,  in  vertebrate 
animals,  the  corpuscles  contain  the  coloring  matter,  and  the 
plasma  is  colorless,  except  in  cephalopods,  where  the  cor- 
puscles have  a  violet  hue,  and  the  terebella,  whose  corpuscles 
are  yellowish-red  (Gscheidlen). 

But  the  red  blood  of  vertebrate  animals  varies  in  its  tint. 
Like  all  other  colored  fluids  (sea-water,  for  instance),  the 
blood  is  darker  when  present  in  quantity.  A  thin  layer  of 
blood  or  a  single  corpuscle  presents  a  faint  amber  hue, 
which  may  be  regarded  as  the  intrinsic  color  of  blood.  The 
freshly  oxygenated  blood  as  it  leaves  the  lungs- and  heart  to 
circulate  throughout  the  body  in  the  arteries  is  a  bright 
scarlet  red.  The  deoxygenated  and  carbonised  blood  as  it 
collects  in  the  veins  to  be  returned  to  the  heart  and  lungs  is 
purple  or  blue.  The  intrinsic  color  of  blood  is  due  to  the 
presence  in  the  corpuscles,  as  one  of  the  ingredients  of  con- 
struction, of  haemoglobin,  which,  as  its  name  implies,  con- 
tains iron.  The  degree  in  which  the  iron  is  oxydiscd  de- 
termines the  tint  of  the  blood.  Thus  the  coloring  matter  of 
the  blood  is  iron,  a  fact  which  gave  to  Mr.  Ruskin  the  oppor- 
tunity for  a  bit  of  sentiment  in  the  comment  that  it  seems 
strange  that  iron,  one  of  the  sternest  and  hardest  substances 


THE  ODOR  OF  THE  BLOOD.  253 

in  nature,  should  be  selected  to  give  expression  in  the  face 
to  the  most  delicate  emotions  of  the  heart. 

"Behold  how  like  a  maid  she  blushes  here: 
Conies  not  that  blood,  as  modest  evidence 
To  witness  simple  virtue?" 

Reaction  of  the  Blood. 

The  blood  of  all  animals  is  alkaline.  We  have  already 
seen  how  this  alkalinity  of  the  blood  favors  oxidation  pro- 
cesses, and  the  importance  of  this  reaction  becomes  evident 
with  the  statement  that  so  soon  as  the  alkalinity  of  the  blood 
of  an  animal  is  neutralised,  by  the  injection  of  an  acid  into  the 
vessels,  the  animal  inevitably  dies.  But  it  is  only  fresh  and 
living  blood  that  exhibits  alkalescense.  Dissolved,  dried 
blood  is  mostly  acid  and  the  alkalescence  of  fresh  blood  con- 
tinues to  diminish  after  withdrawal  from  the  body.  Thus 
40  cubic  centimetres  of  phosphoric  acid  are  required  to 
neutralise  100  cubic  centimetres  of  blood  freshly  drawn, 
while  31  centimetres  suffice  to  neutralise  blood  which  has 
been  drawn  five  minutes.  It  is  by  reason  of  the  alkalinity 
of  the  blood  which  is  chiefly  effected  in  man  by  the  phos- 
phate of  soda  entering  into  its  composition,  that  the  fluidity 
of  the  blood  is  preserved.  Blood  withdrawn  from  the  body 
is  kept  fluid  by  the  addition  of  alkalies,  as  of  ammonia  or 
the  sulphate  of  soda. 

The  Odor  of  the  Blood. 

The  blood  has  a  peculiar  odor,  which  is  different  in  differ- 
ent animals.  Thus  oxen  blood  smells  of  musk,  and  the 
blood  of  many  insects  (caterpillars)  has  an  exceedingly  dis- 
agreeable odor.  In  fact,  it  is  the  blood  which  largely  gives 
the  characteristic  odor  to  the  animal.  The  odor  of  the 
blood  is  due  to  the  existence  in  it  of  certain  volatile  fatty 
acids,  in  alkaline  combinations,  whose  quantity  and  exact 


254  THE  TEMPERATURE  OF  THE  BLOOD. 

nature  is  as  yet  undetermined.  Concentrated  sulphuric 
acid  liberates  the  characteristic  odor  of  the  blood  in  much 
greater  intensity,  or  develops  it  when  not  present  in  sufficient 
degree  to  be  perceptible  (Barruel),  and  valuable  juridical 
evidence  has  been  furnished  in  this  way  in  doubtful  cases. 
This  halitus  sanguinis  of  the  older  physiologists  is  somewhat 
more  marked  in  male  animals.  To  obtain  or  develop  the 
odor  of  the  blood  in  any  intensity,  it  should  be  received 
from  a  vein  in  a  glass  vessel  and  concentrated  sulphuric 
acid  should  be  added  to  it,  in  the  proportion  of  one-third  to 
one  half  the  quantity  of  blood.  The  odor  of  cattle,  sheep, 
dogs  or  fishes  may  be  distinctly  recognised  in  this  way. 

The  odor  of  fresh  human  blood  is  not  very  distinct  at  best. 
It  was  a  psychical  conception  and  not  a  physical  impression 
which  Lady  Macbeth  perceived  with  such  intensity,  when 
in  her  somnambulism  she  muttered : — 

"Here's  the  smell  of  the  blood  still:   all 
the  perfumes  in  Arabia  will  not  sweeten 
this  little  hand." 

The  Taste  of  the  Blood, 

though  not  so  distinctly  characteristic  of  its  source,  is 
nevertheless  peculiar.  The  taste  of  the  salty,  sweet,  and 
extractive  elements  so  mask  each  other  as  to  render  the 
gustative  impression  of  the  blood  sui  generis. 

The  Temperature  of  the  Blood. 

The  blood  is  kept  in  the  body  at  a  temperature  of  about  100° 
F.  (38°C.)  But  much  variation  in  temperature  is  encountered 
in  different  vessels.  The  blood  of  the  surface  capillaries, 
being  cooled  by  exposure,  may  fall,  even  a  degree  or 
two,  according  to  the  external  temperature,  while  in  the 
interior  of  the  body,  it  may  be  elevated  six  or  seven  degrees. 
As  all  chemical  action  develops  heat,  we  might  naturally 


THE  WEIGHT  OF  THE  BLOOD.  255 

infer,  what  direct  observation  positively  confirms,  that  the 
blood  is  warmest  in  places  where  chemical  processes  are 
most  active.  So  the  very  hottest  blood  in  the  body  is  found 
in  the  hepatic  veins,  vessels  which  receive  the  blood  after 
the  intensely  active  chemical  processes  of  the  liver.  The 
temperature  of  the  blood  here  mounts  up  to  107°  F.  (41.6°  C), 
a  degree  which  if  maintained  for  a  length  of  time  upon  the 
surface  of  the  body  would  indicate  inevitably  fatal  oxidation. 
But  the  general  heat  of  the  blood  and  of  the  body  is  almost 
exclusively  sustained  by  the  oxidation  processes  effected 
by  muscular  tissue.  Donyza's  servant  then  gives  his  mis- 
tress proper  counsel  in  the  advice  : — 

"Pray  you  walk  softly,  do  not  heat  your  blood." 

The   Weight  of  the  Blood. 

The  specific  gravity  of  the  blood  varies  between  1054 
and  1060.  To  obtain  it,  the  blood  must  of  course  be 
thoroughly  defibrinated.  This  is  accomplished  by  flagella- 
tion of  the  blood  with  a  wisp  of  straw,  or  by  stirring  it 
with  a  spatula  or  glass  rod.  The  specific  gravity  of  the 
plasma  is  1028,  and  of  the  corpuscles  1088.  The  corpuscles 
being  thus  much  the  heavier,  sink  in  the  plasma  whenever 
the  blood  comes  to  rest.  The  red  corpuscles  being  heavier 
than  the  white  sink  faster,  and  leave  the  white  to  form  the 
"buffy  coat"  on  the  surface  of  the  clot.  The  buffy  coat  is 
thus  no  sign  of  inflammation  (crusta  inflammatoria)  as 
formerly  believed.  It  simply  indicates  in  its  depth  the 
sluggishness  of  coagulation.  It  is  always  seen  in  the  blood 
of  the  horse  withdrawn  from  the  body  of  the  animal.  The 
specific  gravity  of  the  blood  is  markedly  decreased  by 
hemorrhage  and  increased  by  transfusion. 

The  Quantity  of  Blood. 

It  would  seem  to  be  an  easy  matter  to  arrive  at  the  whole 
quantity  of  blood  in  the  body  of  an  animal  by  simply  open- 


250  THE  QUANTITY  OF  BLOOD. 

ing  large  vessels  and  collecting  it  as  it  flows.  But  the  blood 
will  not  all  flow  out  from  the  body.  When  syncope  super- 
venes, the  blood  ceases  to  flow  in  quantity  from  paralysis  of  the 
vaso-motor  nerves,  and  no  posture  can  be  secured  which  will 
permit  gravity  to  effect  the  discharge  of  blood  from  all  the 
vessels. 

A  more  effective  method  is  to  collect  all  the  blood  that 
will  flow  spontaneously,  and  then  wash  out  the  rest  by 
injection  with  a  known  quantity  of  water,  which  could  be 
subtracted  from  the  whole  amount.  The  objection  to  this 
method  lies  in  the  fact  that  a  forcible  injection  would  carry 
out  other  fluids,  lymph,  chyle,  muscular  fluids,  synovial 
serum,  etc.,  which  would  pass  into  the  bloodvessels  by 
diffusion  and  thus  invalidate  conclusions. 

Some  idea  of  the  difficulties  encountered  in  computing 
the  whole  amount  of  blood  may  .be  gathered  from  the 
different  estimates  obtained  by  different  experimenters. 
Thus  Harvey,  Lister,  and  Moulins  compute  that  the  human 
body  contains  about  8  lbs.  of  blood,  Miiller  and  Burdach 
20  lbs.,  Haller  28-30  lbs.,  Hamberger  80  lbs.,  and  Keill 
100  lbs.,  differences  which  sufficiently  exhibit  the  defective- 
ness of  the  methods  employed.  From  among  the  many 
improved  methods  of  more  modern  investigators,  I  may 
mention  that  of  Lehmann  and  Weber  which  consisted  in 
collecting  all  the  blood  which  would  flow  spontaneously 
from  the  divided  vessels  of  decapitated  animals,  washing 
out  the  vessels  until  the  water  injected  escaped  colorless,  and 
then  evaporating  the  fluid  to  a  solid  residue  which  repre- 
sented, of  course,  a  certain  amount  of  blood.  In  this  way 
these  observers  estimated  that  the  proportion  of  blood  to 
the  body  was  about  that  of  one  to  eight ;  that  is,  the  body 
of  a  man  of  average  weight,  145  lbs.,  contains  about  18  lbs. 
of  blood,  a  quantity  too  great  because  of  admixture  with 
other  fluids. 


TIIE  QUANTITY  OF  BLOOD.  257 

Vierordt  made  a  computation  by  multiplying  the  quantity 
of  blood  expelled  from  the  heart  at  each  ventricular  con- 
traction by  the  number  of  beats  required  to  effect  the  entire 
round  of  the  circulation.  If  the  ventricle  pump  out  G.3  oz. 
(an  amount  evidently  too  great),  and  27.7  contractions  are 
necessary  to  effect  the  round  of  the  circulation,  as  he 
maintains,  the  proportion  of  blood  to  the  body  would  be 
fa- fa  about  11-12  lbs.  Welcker  first  employed  the  color 
test,  which  consists  in  mincing  the  body  of  the  animal  after 
all  its  blood  has  escaped,  and  been  washed  out.  The  mince 
meat  was  then  infused  and  the  color  of  the  infusion  compared 
with  that  of  previously  prepared  color  tests  containing 
a  known  quantity  of  blood.  Welcker  concluded  that  the 
body  of  a  man  (143  lbs.)  contains  about  11  lbs.  of  blood. 
Preyer's  spectroscopic  test  (estimation  of  the  amount  of 
haemoglobin)  yields  about  the  same  result,  as  does  also  the 
entirely  different  method  of  Brozeit,  which  consisted  in  the 
recovery  of  the  haematin  from  the  washed  out  blood,  so  that 
this  proportion,  the  fa  may  be  assumed  to  represent  the 
amount  of  blood  in  the  body.  The  proportion  of  blood  to 
the  rest  of  the  body  in  different  animals  is  about  as  follows : 
guinea  pig,  tW*,  rabbit  fa-^Ut  doS  tVtV,  cat  fa  birds 

tVtV >  f ™SS  TTio.  fisnes  TV-A- 
lt must  not  be  forgotten,  of  course,  that  the  quantity  of 

blood  varies  very  greatly  at  different  times  of  the  day,  with 

reference  especially  to  the  hours  of  taking  food.     Bernard 

illustrated  this  fact  by  drawing  ten  and  a  half  ounces  of 

blood  from  a  rabbit,  after  eating,  without  serious  result  to 

the  life  of  the  animal,  whereas  the  withdrawal  of  five  ounces 

proved  fatal  to  the  animal  fasting.     According  to  Colard  de 

Martigny,  the  quantity  of  blood  in  a  rabbit,  in  a  healthy 

well-fed  state,  is  about  30  grammes,  which  is  reduced  by 

three  days  fasting  to  20  grammes,  and  by  ten  days  fasting  to 

only  7  grammes.     This  great   variation   with   reference  to 


258  THE  MORPHOLOGY   OF  THE  BLOOD. 

meals  may  account,  as  Carpenter  suggests,  for  the  wide  dis- 
crepancies observable  in  different  estimates  of  the  whole 
quantity  of  blood.  Then  the  average  quantity  is  widely 
departed  from  in  cases  of  plethora  and  anaemia.  Thus 
Wrisberg  states  that  a  plethoric  woman,  who  died  of  metro- 
rhagia,  lost  26  lbs.  of  blood,  and  reports  the  fact  that  as 
much  as  24  lbs.  was  collected  from  the  vessels  of  a  woman 
who  had  suffered  death  by  decapitation. 

The  Morphology  of  the  Blood. 

The  blood  as  it  flows  from  a  divided  vessel  is  apparently 
a  perfectly  homogeneous  fluid.  But  on  examination  under 
the  microscope  it  is  seen  to  contain,  in  myriad  numbers, 
certain  formed  elements,  the  corpuscles.  The  corpuscles 
seem  to  occupy  about  half  the  space  in  the  microscopic 
field.  It  was  not  given  to  Harvey,  the  discoverer  of  the 
circulation  of  the  blood,  to  ever  see  the  blood  corpuscles  or 
the  capillaries  in  which  their  course  and  conduct  in  life  are 
distinctly  visible.  The  blood  corpuscles  were  first  recognised 
by  Malpighi  (1661),  as  peculiar  and  hitherto  unrecognised 
particles,  floating  in  the  current  of  the  blood.  Malpighi, 
however,  did  not  appreciate  their  significance  ;  he  regarded 
them  as  particles  of  fat.  It  was  only  then  after  the  lapse 
of  twelve  years,  that  Leeuwenhoek  was  able  to  describe  the 
true  nature  of  the  red  corpuscles,  as  morphotic  elements, 
always  present  in  the  blood.  And  it  was  not  until  a  hundred 
years  later  still,  that  the  second  variety  of  bodies,  the  white 
corpuscles,  were  pointed  out  by  a  distinguished  English 
observer,  Wm.  Hewson.  The  recognition  of  the  morphotic 
elements  of  the  blood,  was  then  only  finally  complete  with 
the  discovery  by  Schultze  (1865)  of  certain,  minute,  irregular, 
colorless,  granules,  distinguished  by  their  varying  quantity 
and  their  great  refrangibility.'  As  we  have  as  yet  no 
knowledge  of  these  bodies,  other  than  that  of  their  existence, 


THE   11ED   BLOOD   CORPUSCLES.  259 

we   may   pass  to   the   consideration  of  the  elements  with 
whose  nature  and  use  we  are  most  familiar. 

The  Bed  Blood  Coiyuscles. 

There  is  a  description  of  the  red  blood  corpuscle  that  is 
so  concise  and  complete  as  to  have  been  adopted  in  most 
works  on  physiology.  The  blood  corpuscles  are  described 
viz.,  as  "flattened,  biconcave,  circular  disks."  So,  then,  we 
may  say,  roughly,  that  red  blood  corpuscles  look  like 
biconcave  lenses,  or  like  crackers  (butter  crackers),  without 
their  central  elevation.  The  camel  and  the  lama  are  the 
only  mammals  whose  corpuscles  depart  from  this  shape,  in 
that  in  these  animals,  the  red  corpuscles,  like  those  of  fishes, 
amphibious  animals,  reptiles,  and  birds  are  elliptical.  The 
exceptional  shape  of  the  corpuscles  in  the  camel  species  is 
very  remarkable,  in  that  the  small  family  of  the  camelidse 
is  thus  distinguished  alone  among  all  mammals.  Milne 
Edwards  sought  for  elliptical  corpuscles  in  more  than  200 
species  selected  from  all  the  natural  subdivisions  of  this 
group,  but  could  not  find  them  "even  among  the  marsupials 
and  monotremata,  which  seem,  in  certain  respects,  to  establish 
a  transition  between  ordinary  mammals  and  oviparous 
vertebrates."  The  elliptical  shape  of  the  blcod  corpuscles 
of  the  camel  tribe,  like  the  existence  in  the  small  intestine, 
of  the  same  tribe,  of  valvulse  conniventes,  which  were  once 
believed  to  be  characteristic  of  man,  is,  when  properly 
interpreted,  additional  evidence  of  the  mutability  of  species. 

In  the  study  of  the  structure  and  properties  of  red  blood 
corpuscles,  the  precaution  must  always  be  taken  to  add  to 
the  specimen  of  blood  some  diluent.  Else,  the  corpuscles 
speedily  shrink  from  evaporation  of  their  fluid  contents, 
become  crenated  upon  their  edges,  and  finally  shrivel  away. 
But  the  character  of  the  diluent  must  be  selected  with 
caution.     The  addition  of  simple  water  dissipates  the  cor' 


260  SIZE  OF  THE  BLOOD  CORPUSCLES. 

puscles  from  the  field  in  a  very  few  minutes.  The  water 
is  very  quickly  absorbed,  the  coloring  matter  is  separated,  the 
corpuscles  swell  to  colorless  spheres,  burst,  or  are  entirely 
dissolved  from  vision.  The  best  fluid  in  which  to  preserve 
corpuscles  is  the  natural  serum  of  the  blood,  and  the  serum 
should  be  taken  from  the  same  animal  or  from  the  same 
species  of  animal.  For,  according  to  Landois,  the  blood 
corpuscles  of  the  rabbit,  for  instance,  are  transformed, 
on  the  addition  of  the  serum  from  dogs  blood,  to  spheres 
or  balls,  and  the  coloring  matter  is  dissolved  out.  In  the 
absence  of  serum,  a  six  per  cent,  solution  of  common  salt 
exercises  the  least  injurious  effect  upon  the  size,  shape,  and 
structure  of  the  corpuscles.  Blood  corpuscles  (of  any  ani- 
mal) are  best  preserved  by  holding  a  thin  layer  of  blood 
over  an  aqueous  solution  of  perosmic  acid,  in  such  a  way 
that  its  vapor  may  pass  to  the  blood.  The  blood  corpuscles 
are  hardened  in  this  way,  without  change  of  form  or  color. 
They  maintain  also  their  central  depression  and  become  so 
consistent  that  they  may  be  kept  unaltered  for  a  very  long 
time  in  water  or  in  glycerine.  It  is  the  central  depression 
which  gives  to  red  corpuscles  their  peculiar  optical  appear- 
ance. Either  the  centre  is  dark  and  the  circumference  light, 
or  vice  versa,  according  as  one  or  other  is  in  focus. 

Size  of  the  Blood  Corpuscles. 

By  means  of  a  micrometer  it  is  not  difficult  to  measure 
the  exact  size  of  the  blood  corpuscles  of  an  animal,  a  point 
of  great  medico-legal  interest.  Yet  there  is  by  no  means 
that  unaminity  of  statement  upon  this  subject  that  might 
naturally  be  expected.  Thus  Kulliker,  the  highest  German 
authority  says,  as  regards  human  corpuscles,  that  95  out  of 
every  100  corpuscles  measure  ^p  of  an  inch  (0.0071  mm.) 
in  diameter ;  Robin,  tjie  highest  French  authority  states  the 
exact  diameter  to  be  ^Vr  °*  an  *ncu  (0.0073  mm.) ;  while 


SIZE   OF   THE   BLOOD   CORPUSCLES.  261 

Gulliver,  who  examined  the  corpusclesof  all  the  animals  in  the 
London  Zoological  Garden,  and  hence  had  great  experience 
in  measurements,  puts  the  diameter  of  human  corpuscles  at 
■52W  °f  an  inch,  a  fraction  which  is  undoubtedly  too  high. 

That  there  is  no  relation  whatever,  between  the  size  of 
an  animal  and  the  size  of  its  blood  corpuscles  is  evidenced 
by  reference  to  Gulliver's  table,  showing  the  size  of  the 
corpuscles  in  176  mammals.  The  ox,  for  example,  a 
very  large  animal,  has  a  blood  corpuscle  whose  diameter  is 
exceedingly  small,  T^Vr  °f  an  inch,  much  smaller,  thus,  than 
that  of  the  corpuscles  of  man ;  while  the  cat,  a  small  animal, 
has  a  corpuscle  -^W  °f  an  inch  diameter,  very  nearly  as 
large  as  that  of  the  ox,  and  the  mouse,  which  is  much 
smaller  than  the  cat,  has  a  much  larger  corpuscle,  viz., 
^ttt  °f  an  inch  diameter,  much  larger,  thus,  than  that  of 
the  ox. 

Milne  Edwards  has  endeavored  to  show  that  there  is  an 
inverse  relation  between  the  size  of  the  corpuscle  and  the 
muscular  activity  of  the  animal,  that  is,  the  more  active 
animals  have  the  smallest  corpuscles.  There  is  much 
foundation  for  this  observation,  which  may,  indeed,  be 
considered  a  rule,  but  it  is  a  rule,  not  without  exceptions. 
Thus  the  dog,  a  very  active  animal,  has  a  corpuscle  which 
is  generally  regarded  as  having  exactly  the  dimensions  of 
the  human  corpuscle,  viz.,  -g-Jjjrr  of  an  inch,  while  the  ox,  a 
very  sluggish  animal,  has  a  mnch  smaller  corpuscle,  ^^^  of 
an  inch.  As  the  size  and  shape  of  blood  corpuscles  are 
among  the  chief  factors  in  the  identification  of  blood,  and  its 
source,  it  is  important  to  have  definite  and  accurate  data 
concerning  every  point.  The  differentiation  of  human  blood 
from  that  of  fishes,  reptiles  and  birds,  never  offers  the  least 
difficulty,  because  of  the  elliptical  shape  of  their  corpuscles. 
They  are  not  only  ellipses,  whose  long  diameter  is  about 
twice  as  great  as  the  broad  diameter^  but  they  are  also 


262  SIZE  OF   THE  BLOOD  CORPUSCLES. 

distinctly  embossed  (biconvex).  But  the  differentiation  of 
human  blood  from  that  of  lower  mammals  is  effected  with 
great  difficulty  and  in  some  cases  can  not  be  effected  at  all. 

The  most  recent  and  reliable  measurements  of  blood  cor- 
puscles have  been  furnished  by  Welcker,  who  estimated 
the  size  of  his  own  blood  corpuscles  from  130  observations 
as  follows : — 

Greatest  transverse  diameter        -         0,00774  mm. 
thickness    -        -        -        -    0.00190     " 

These  measurements  were  made  by  introducing  into  the 
eye-piece  of  a  microscope,  a  micrometer,  whose  lines  stood, 
under  a  magnification  of  620  diameters,  0.001723  mm.  apart, 
and  the  tenths  of  a  division  could  be  estimated  with  accu- 
racy. The  blood  corpuscles  were  suspended  in  serum,  and 
evaporation,  as  well  as  agitation,  was  prevented  by  fastening 
down  the  edges  of  the  cover  glass  with  Canada  balsam 
(Gscheidlen). 

Welcker  also  made  measurements  in  the  case  of  other  ani- 
mals as  follows : — 

Animals.  No.  of  Observations.         Average  Diameter. 

Elephant  20                        0.0094  mm. 

Dog   -  10  -           0.0073  " 

Eabbit  -        -        -        20        -        -      0.0069  " 

Cat  -        -            20  -           0.0065  " 

Sheep  20                        0.0050  " 

Goat  20  -           0.0041  " 

Deer  -                            5                        0.0025  " 

And  of  animals  having  elliptical  corpuscles  as  follows: — 

Animals.         No.  Obs.     Long-  Diameter.  Short  Diameter. 

Lama  20  0.0080  0.0040  mm. 

Pigeon  20  0.0147  0.0065     " 

Frog  50  0.0223  0.0157     " 

Triton  20  0.0293  0.0195     " 


ELASTICITY  OP  THE  HED  CORPUSCLE.  263 

The  Number  of  Red  Corpuscles, 

The  number  of  blood  corpuscles  in  a  given  quantity  of  blood 
may  be  ascertained  by  directly  counting  them  in  a  known 
quantity  under  the  microscope,  and  multiplying  this  known 
quantity,  a  fractional  part  of  a  drop,  by  the  whole  quantity 
under  consideration.  A  better  method,  however,  is  to 
dilute  a  known  quantity  of  blood  with  a  known  quantity  of 
serum  or  salt  solution,  and  then  count  and  compute  as  before. 
From  these  methods  it  is  estimated  that  a  cubic  centimetre 
of  human  blood  contains  4,231,500  (Stoltzing),  4,620,000 
(Welcker),  5,174,000  (Vierordt),  corpuscles.  In  ansemia, 
leucocythsemia,  etc.,  this  number  may  be  reduced  by  millions, 
to  be  again  restored  by  chalybeate,  or  other  suitable  treat- 
ment. The  whole  number  of  corpuscles  in  the  blood  of  a  man 
of  average  weight  is  roughly  estimated  at  about  twenty-five 
billions. 

Elasticity  of  the  Red  Corpuscle. 

The  red  blood  corpuscles  are  highly  elastic  bodies.  When 
studied  under  the  microscope  it  is  observed  that  pressure  of 
the  cover  upon  the  object  glass  flattens  them,  but  they 
speedily  recover  their  original  shape  and  size  when  the  pres- 
sure is  relieved.  Observed  in  the  capillary  vessels  (web  of 
frog's  foot,  tail  of  lizard,  mesentery  of  mouse,  or  lung  of 
frog)  they  are  seen  to  become  elongated  almost  to  a  thread, 
and  thus  succeed  in  traversing  capillaries  whose  diameter  is 
much  less  than  their  own,  to  resume  their  original  size  and 
shape  on  escape  into  wider  tubes.  So  they  are  sometimes 
caught  at  an  angle,  formed  by  the  division  of  one  capillary 
into  two,  and  to  be  swung  first  partly  into  one  tube,  then 
partly  into  another,  changing  their  shape  (passively)  con- 
tinually, until,  finally,  sufficient  vis  a  tergo  from  the  proper 
direction  sweeps  them  entirely  into  one  or  other  tube.     The 


264  THE  CONSTITUTION  OF  THE  CORPUSCLES. 

elasticity  of  the  corpuscle  is  also  manifest  in  the  constant 
change  of  shape  they  are  made  to  undergo  under  permeation 
and  surrender  of  various  gases.  Carbonic  acid  gas  distends 
the  corpuscle,  and  oxygen  leaves  them  more  flat,  a  factor 
which  partially  effects  the  difference  of  color  between  arterial 
and  venous  blood.  The  red  corpuscles,  therefore,  are  rather 
semi-fluid  than  semi-solid.  They  are  to  be  regarded  as 
thoroughly  homogenous  bodies,  like  particles  of  jelly  and 
are  in  no  sense  cells,  in  the  ordinary  acceptation  of  the  term, 
with  walls,  contents  and  nuclei. 

Constitution  of  the  Corpuscles. 

The  red  blood  corpuscles  are  composed  of  a  gelatinous  basis; 
the  stroma,  and  the  iron  containing,  albumenoid,  coloring 
matter ;  the  haemoglobin.  The  haemoglobin  is  easily  soluble 
in  water  or  serum  but  is  so  intimately  blended  with  the 
stroma,  as  to  require  artificial  intervention  to  effect  its 
separation.  If  blood  be  repeatedly  frozen  and  thawed,  or  if 
successive  strokes  of  electricity  be  transmitted  through  its 
mass,  the  haemoglobin  is  separated,  and  is  held  in  solution 
by  the  plasma,  so  that  the  blood  loses  its  opacity  (which 
is  due  to  the  different  angles  at  which  the  corpuscles  and  the 
plasma  refract  light)  and  becomes  quite  translucent  like 
colored  varnish.  Dilution  with  water,  the  addition  of  bile 
salts,  agitation  with  ether,  chloroform,  alcohol  or  bisulphide 
of  carbon  effect  the  same  result  (Fick).  So  also  septic 
and  miasmatic  germs,  in  disorganising  the  corpuscles,  liber- 
ate the  coloring  matter,  so  that  the  skin,  mucous  membranes, 
in  fact,  all  the  tissues,  become  stained  with  it.  This  con- 
stitutes the  hematogenous  icterus  of  yellow,  malarial,  typhus, 
etc.,  fevers.  The  haemoglobin  when  thus  separated  assumes 
special  rhombic  forms  which  may  be  differentiated  from 
the  forms  assumed  by  the  haemoglobin  of  lower  animals. 
One  of  the  most  reliable  of  all  the  tests  for  blood  is  the 


THE  USE  OF  THE  RED  BLOOD  CORPUSCLE.      265 

spectroscopic  test  afforded  by  the  lines  formed  in  the  spectrum 
by  hemoglobin,  when  oxidised  (oxyhemoglobin),  as  in 
arterial  blood,  or  when  reduced,  as  in  venous  blood.  Reduced 
hemoglobin  distinguishes  itself  by  an  absorption  band 
in  the  yellow  part  of  the  spectrum.  If  new  this  solution 
of  reduced  hemoglobin  be  agitated  with  oxygen,  the  absorp- 
tion band  falls  into  two,  one  of  which  approaches  the  line 
D,  the  other  the  line  E  of  the  solar  spectrum,  and  the  space 
formerly  occupied  by  the-  absorption  band  of  the  reduced 
hemoglobin  is  now  clear.  Hemoglobin  on  standing  for  any 
length  of  time  separates  into  an  albumenoid  substance  and 
the  iron  coloring  matter  hematin.  The  addition  of  acids 
effects  the  same  division.  Hematin,  dissolved  in  ether  or  in 
alkalies,  or  reduced,  gives  also  special  bands  in  the  spectrum. 
The  stroma  of  the  corpuscles  is  a  very  complicated  com- 
bination of  an  albumenoid  substance  (protagon  or  lecithin) 
with  salts  of  potash  and  phosphorus  and  with  fats  and 
cholesterine.  It  is  markedly  hygroscopic,  swells  by  imbibi- 
tion with  water,  and  thus  restores  the  size  and  shape  of 
blood  corpuscles  after  the  dessication  of  years.  Blood 
stains,  shaved  up  from  floors  or  scraped  from  knives,  have 
been  recognised  as  such,  by  this  restoration  of  the  size  and 
shape  of  dried  corpuscles,  after  the  lapse  of  several  years. 

Use  of  the  Red  Blood  Corpuscles. 

The  red  blood  corpuscles  are  the  oxygen  carriers  to  the 
tissues.  They  arrive  at  the  lungs  partly  emptied  of  oxygen, 
receive  an  additional  quantity  as  the  result  of  inspiration, 
and  are  swept  off  into  the  general  circulation  by  the  action 
of  the  heart.  In  the  capillaries,  the  oxygen,  a  great  part  of 
it,  at  least,  is  surrendered  to  the  tissues,  and  carbonic  acid 
gas  is  received  in  its  place.  The  blood  corpuscles  have  the 
property  of  absorbing  ten  to  thirteen  times  as  much  oxygen 
as  water.    The  blood  plasma  will  absorb  two  or  three  times 

23 


266  THE  COLORLESS  BLOOD  CORPUSCLES. 

as  much  oxygen  as  water,  and  this  constituent  officiates  in 
its  conduction,  though  to  much  less  degree  than  in  the  con- 
duction of  carbonic  acid  gas. 

The  red  corpuscles  being  thus  so  distinctly  the  oxygen 
carriers,  any  marked  diminution  in  their  amount  should 
produce  symptoms  of  asphyxia.  And,  in  fact,  it  is  observed 
that  animals  dying  of  hemorrhage  experience  first  vertigo 
and  syncope,  from  lack  of  oxygen  for  nervous  supply, 
become  finally  convulsed,  and  die  panting  for  air.  So  Paul 
Bert  has  shown  that  the  resistance  to  asphyxia  manifested 
by  diving  animals,  so  long  inexplicable,  is  due  to  the  simple 
fact  that  these  animals  have  more  blood,  and  consequently 
more  blood  corpuscles.  Thus  a  chicken  can  be  drowned  or 
strangled  in  two  minutes,  while  a  duck  of  the  same  weight 
will  survive  seven  or  eight  minutes.  The  duck  has,  how- 
ever, one-third  or  one-half  more  blood  than  the  chicken, 
and  each  additional  corpuscle  is,  of  course,  an  additional 
reservoir  of  oxygen  gas. 

The  Colorless  Blood  Corpuscles. 

Colorless  corpuscles  exist  in  the  blood  of  both  vertebrate 
and  invertebrate  animals.  The  first  noticeable  fact  con- 
cerning the  white  corpuscles  in  the  blood  of  man  is  their 
comparative  paucity.  They  exist  in  the  proportion  of  one 
to  three  to  four  hundred  of  the  red  corpuscles,  but  their 
absolute  and  relative  number  varies  greatly  according  to  the 
period  of  observation.  That  is,  they  are  very  markedly  in- 
creased after  meals.  Thus  Hirt  found  them  present  before 
breakfast,  at  the  period  of  greatest  fasting,  in  the  proportion 
of  1:1800,  after  breakfast  1:700,  before  dinner  1:1500,  after 
dinner  1:400,  etc. 

The  white  blood  corpuscle  diners  from  the  red  in  other 
respects  than  color.  In  the  first  place  it  is  larger  than  the 
red.    Though  Schultze  describes  three  different  sizes  of 


THE  COLORLESS  BLOOD  CORPUSCLES.  267 

white  corpuscles,  that  which  exists  in  greatest  number  and 
which  is  mostly  studied,  measures  vr-1^  of  an  inch  (0.0101  mm.) 
in  diameter.  Secondly,  the  white  blood  corpuscle  is  not  a 
disk.  It  is  spherical  in  shape.  It  differs  additionally  in 
being  abundantly  granulated,  and  in  containing  a  distinct 
nucleus. 

Bodies  which  have  always  been  regarded  as  similar,  and 
which  are  now  known  to  be  identical  in  every  respect  to 
white  corpuscles,  are  found  also  in  the  lymph  and  chyle,  in 
colostrum,  semen  and  in  the  vitreous  humor  of  the  eyeball. 
Such  bodies  constitute  the  morphotic  elements  of  pus,  where 
they  are  known  as  pus  cells. 

But  what  especially  distinguishes  white  blood  corpuscles 
(leucocytes),  is  their  property  of  motion.  They  move  like 
the  amoebae,  which  we  have  already  studied,  and  hence  are 
often  known  as  the  amoeboid  cells.  Circulating  in  the  ves- 
sels, they  keep  close  to  the  wall  of  the  vessel,  while  the  red 
corpuscles  form  an  axial  mass  in  quicker  motion. 

This  amoeboid  motion  of  the  white  corpuscles  may  be  very 
easily  brought  under  observation.  A  watch  glass  is  filled 
with  frogs  blood,  which  is  allowed  to  coagulate.  The  coagu- 
lum  is  then  separated  with  a  needle  from  the  edge  of  the 
glass,  and  when  a  little  serum  has  exuded,  a  drop  of  it  is  let 
fall  upon  a  .cover  glass,  which  is  then  placed  upon  an  object 
glass,  so  arranged  that  it  can  be  kept  warm.  The  edge  of 
the  object  glass  should  be  covered  with  oil,  to  prevent 
evaporation.  The  object  glass  is  now  to  be  gently  heated. 
So  soon  as  the  temperature  rises  to  36°  C.  (96°  F.)  the  well 
known  processes  of  motion  ensue.  The  movements  of  the 
white  corpuscles  of  human  blood,  and  their  response  to 
various  stimulants,  may  be  studied  in  the  same  way.  The 
white  blood  corpuscles  represent  the  incunabular  stages  of 
the  red  corpuscles,  as  transition  forms  have  been  discovered 
in  abundance  in  the  lymph  glands,  in  the  spleen,  thymus 


268 


THE  BLOOD  PLASMA. 


and  thyroid  glands,  supra-renal  capsules,  marrow  of  bones, 
etc.,  structures,  all  of  them,  found  only  in  vertebrate  ani- 
mals, in  which  alone  red  corpuscles  are  found. 

The  Blood  Plasma. 

The  plasma  contains  all  the  remaining  ingredients  of 
the  blood  except  the  corpuscles.  To  obtain  a  satisfactory 
analysis  of  the  plasma  it  is  necessary  to  examine  the  blood 
before  coagulation  and  after  the  sinking  of  the  corpuscles. 
As  the  corpuscles  sink  very  rapidly  in  the  blood  of  the 
horse,  leaving  a  supernatural  clear  plasma,  the  most  reliable 
results  have  been  obtained  from  this  animal.  The  following 
table  exhibits  the  composition  of  the  blood  of  the  horse : 


1000 
Parts 
Blood 
Cont'n 


r  Water 

184.30 
'  Haemoglobin  122.75 

'  Corpuscles  324.2   ' 

Solids 

Albumen           17.80 

[  141.9 

Lecithin              0.84 

Cholesterin         0.51 

'  Water 

579.4 
"  Fibrin                   6.4 

^  Plasma  673.8 

Albumen            43.1 

Solids 

Fat                        0.8 

b     58.4 

Extracts                2.5 

Soluble  Salts        4.1 
Insoluble  Salts     1.1 

No  fluid  in  the  body  has  been  subjected  to  so  many  and  such 
careful  and  skilful  analyses  as  the  blood,  but  the  conclusions 
reached  by  different  observers  have  shown  very  marked 
differences.  When  we  recall,  however,  what  changes  the 
blood  must  undergo,  not  only  daily,  and  hourly,  but  in  every 
second  of  time,  in  yielding  up  constituents  for  continu- 
ous supply,  and  in  receiving  as  continuously  the  products 
of  combustion  and  waste,  we  cease  to  wonder  at  any  quanti- 
tative or  qualitative  discrepancies  in  the  results  of  chemical 
analyses. 

"Xor  are,  although  the  river  keep  the  name 
Yesterday's  waters  and  to-day's  the  same." 


THE   COAGULATION   OF  THE  BLOOD.  269 

The  blood  in  its  entirety  contains,  thus,  proximate  princi- 
ples of  the  three  different  classes ;  of  the  inorganic  class  in 
its  water,  iron  and  salts,  of  the  non-nitrogenous  class  in  its 
fat,  extractives  and  part  of  the  lecithin,  and  of  the  nitro- 
genised  class  in  its  albumen,  globulin  and  fibrin.  Hence  it 
is  that  the  blood  is  the  pabulum  of  all  the  tissues.  It 
contains  the  materials  out  of  which  the  protoplasm  of  all 
the  tissues  may  evolve  work,  that  is  fuel,  and  it  contains 
materials  from  which  the  tissues  may  repair  their  own 
waste.  But  all  these  matters  do  not  really  exist  in  the 
blood  as  such,  and  hence  are  not,  strictly  speaking,  proximate 
principles.  This  is  notably  the  case  with  regard  to  fibrin. 
Fibrin  does  not  exist  in  the  blood  as  such,  and  only  presents 
itself  as  an  ingredient  when  physiological  conditions  are  in 
some  way  disturbed.  Fibrin  is  a  product  of  two  substances, 
the  so-called  fibrin  generators,  paraglobulin  and  fibrin- 
ogen (A.  Schmidt).  Both  these  substances  exist  as  such 
in  the  blood,  and  may  be  recovered  from  it  by  suitable 
manipulation.  Nor  is  the  albumen  in  the  blood  the  same 
as  ordinary  albumen  (white  of  egg).  It  differs  from  it  in 
many  chemical  reactions,  and  more  especially  in  its  osmotic 
properties.  If  ordinary  albumen  be  injected  into  the  blood, 
it  is  not  absorbed,  but  is  rejected  by  the  kidneys,  while 
blood  albumen  is  retained  and  absorbed. 

The  Coagulation  of  the  Blood. 

Within  five  minutes  after  blood  is  withdrawn  from  the 
body  it  begins  to  clot.  A  gelatinous  pellicle  first  forms 
upon  its  surface  and  afterwards  extends  down  the  sides  of 
the  vessel  containing  the  blood.  When  the  vessel  is  now 
agitated,  the  mass  of  blood  does  not  spill  out ;  it  quivers 
like  a  mass  of  jelly.  Gradually  now  the  process  of  coagula- 
tion invades  the  whole  mass  of  the  blood  until,  finally,  the 
entire  quantity  has  become  "set."    The  time  occupied  in 


270  THE  COAGULATION  OF  THE  BLOOD. 

this  solidification  of  the  whole  mass  is,  according  to  Nasse, 
from  seven  to  sixteen  minutes.  The  clot  next  begins  to 
contract,  and  pellucid  drops  of  fluid  exude  from  its  surface. 
The  further  process  of  coagulation  consists  in  the  continua- 
tion of  contraction  of  the  coagulum  and  expression  of 
fluid  until,  in  from  10-12  hours,  the  whole  mass  of  the  blood 
has  become  separated  into  "a  clot"  and  surrounding  "serum." 
The  clot  is  composed  of  the  fibrin,  entangling  the  corpuscles, 
and  the  serum  contains  the  water,  the  albumen  and  the 
salts. 

The  coagulation  of  the  blood  depends  upon  the  fact 
that  the  fibrin  generators,  when  placed  under  abnormal  con- 
ditions, pass  from  the  fluid  to  the  solid  state,  that  is,  that 
the  fibrin  generators  unite  to  generate  fibrin.  If  a  drop  of 
blood  be  observed  under  the  microscope,  this  gradual 
development  of  fibrin  manifests  itself  in  the  formation  of 
threads  or  fibrillar,  which  extend  across  the  microscopic  field, 
entangling  the  corpuscles,  Avhich  have  now  become  packed  up 
against  each  other,  in  rows  or  rouleaux,  like  coins  upon  a 
banker's  table.  The  corpuscles  escape  entanglement  if  time 
be  allowed  for  their  subsidence.  Thus  when  the  blood 
coagulates  slowly,  naturally,  or  artificially  (as  by  the  addition 
of  alkalies),  the  corpuscles  gravitate  to  the  bottom  of  the 
vessel.  The  position  of  the  body  at  death,  after  subsequent 
change,  has  sometimes  been  determined  by  the  location  of 
the  corpuscles  in  the  clot,  as  in  the  longitudinal  sinus.  We 
have  as  yet  no  satisfactory  explanation  of  the  cause  of  the 
coagulation  of  the  blood.  None  the  less,  however,  are  we 
able  to  appreciate  its  utility.  Were  it  not  for  this  forma- 
tion of  fibrin  under  certain  conditions,  to  officiate  as  a  plug 
for  divided  vessels,  the  slightest  solution  of  continuity  in 
the  walls  of  a  bloodvessel  would  be  attended  with  fatal 
hemorrhage.  In  fact  there  are  cases  characterised  by  a 
deficiency  in  its  formation,  the  so-called  cases  of  hemorrhagic 


THE  COAGULATION  OF  THE  BLOOD.  271 

diathesis  in  which  the  extraction  of  a  tooth,  the  scratch  of 
a  pin,  the  slightest  lesions,  permit  the  most  disastrous 
hemorrhage.  In  these,  cases,  pressure  or  ligation  of  vessels, 
if  of  sufficient  size,  affords  only  temporary  relief.  When 
the  pressure  is  relieved,  or  the  ligature  comes  away,  the  hem- 
orrhage, of  course,  recurs.  Ordinarily,  however,  the  coagu- 
lating blood  blocks  the  orifice  in  the  wounded  vessel,  and  thus 
checks  further  loss.  The  great  vessels  in  the  walls  of  the  uterus, 
after  the  extensive  lacerations  of  parturition,  are  stuffed  by 
clots  of  blood  and,  further  escape  is  thus,  as  a  rule,  prevented. 
Thus,  also,  successive  layers  of  fibrin  are  sometimes  deposited 
in  the  walls  of  a  vessel,  weakened  and  distended  by  disease 
(aneurism),  so  that  the  weakest  places  become  the  strongest 
by  this  adventitious  padding.  Unfortunately,  fibrin  some- 
times exercises  a  more  malign  influence,  in  being  swept  off 
in  the  torrent  of  the  circulation,  from  surfaces  upon  which 
it  has  become  deposited,  to  distant  places,  to  block  up  most 
important  vessels.  Masses  of  fibrin  (emboli)  are  thus 
occasionally  detached  from  valves  of  the  heart,  upon  which 
they  have  come  to  be  deposited,  in  consequence  of  the 
roughening  induced  by  endocardial  inflammations,  and 
carried  to  plug  the  great  vessels  feeding  the  brain,  and  thus 
cause  the  most  serious  lesions,  and  often  death. 

Here,  then,  we  must  conclude  our  brief  survey  of  the 
properties  of  the  blood.  And  whether  we  look  upon  it  in 
the  light  of  its  mere  complexity  of  construction,  of  the  grave 
symptoms  induced  by  even  its  partial  loss,  of  its  speedy 
reproduction  after  hemorrhage,  of  its  maintenance  of  itself 
under  the  constant  consumption  which  it  must  suffer,  we 
can  not  fail  to  appreciate  its  importance.  Magendie  says 
that  a  celebrated  physiologist  became  so  convinced  of  the 
value  of  the  blood  as  to  define  life  as  "the  contact  of  arterial 
blood  with  the  organs  of  the  body,  especially  with  the 
brain."     If  he  had  said,  the  consumption  of  the  blood  by 


272  THE  BLOOD  AS  THE  SOURCE  OF  LIFE. 

the  organs,  and  liberation  of  its  latent  force,  he  would 
have  told  all  the  truth.  The  older  physiologists  were 
fond  of  locating  life  as  a  peculiar  principle  or  essence 
in  the  blood.  It  lodged  in  the  pure  or  arterial  blood. 
It  was  the  promulgation  of  this  delusion,  that  the  soul 
dwelt  in  the  arterial  blood,  that  cost  Servetus  his  life. 
Such  temerity  as  the  attempt  to  localise  the  soul  awakened 
the  ire  of  the  theologians,  and  at  the  instigation  and  by  the 
order  of  John  Calvin,  Servetus  was  publicly  burned  at  the 
stake  in  Geneva,  and  nearly  every  copy  of  his  works  was 
thrown  into  the  flames. 

The  older  clinicians  waged  bitter  war  among  themselves 
concerning  the  part  the  blood  played  in  disease.  The 
"humoral"  pathologists  maintained  that  the  blood  was  the 
seat  of  all  disease.  Much  of  the  popular  conceit  of  our  own 
times  regarding  "impurities"  of  the  blood  is  derived  from 
the  doctrines  of  humoral  pathology.  The  impurities,  which 
we  are  called  upon  to  treat,  are,  for  the  most  part,  impurities 
of  the  skin,  animal  and  vegetable  parasites,  with  which  the 
blood  has  nothing  to  do,  except  to  nourish  their  host.  The 
real  impurities  of  the  blood  are  the  acute  infectious  dis- 
eases, the  germs  of  which  breed  in  the  blood,  with  character- 
istic fecundity,  feed  upon  it,  disorganise  and  corrupt  it,  so 
that : — 

"The  life  of  all  his  blood  is  touched  corruptibly." 

The  blood,  as  the  source  of  life,  has  always  been  recognised 
as  the  maternal  substitute  of  the  body  from  which  it  is 
derived.  The  contract  for  the  sale  of  the  soul  had  always 
to  be  signed  in  blood.  So  Mephistopheles  insists  that  Faust 
shall  sign  his  compact  with  him  with  a  pen  dipped  in  his 
blood,  because  as  he  says  of  this  subtle  fluid — a  saying  to 
which  we  are  now  prepared  to  agree: — "Blub  ist  ein  ganz 
besonderer  Saft"  (Blood  is  a  very  peculiar  juice). 


INDEX. 


PAGE. 

Absorption  and  assimilation  132 

Adaptation,  force  of. 90 

Age,  determination  of 1C7, 1G8 

"       effect  of  upon  nerve  tissue 245 

"       of  the  earth 59 

Air  in  bone 170 

Albumen   and  its  products 130 

"  of  the  blood.., 2G9 

Alcohol,  action  of. 12 

Alkalinity  as  favoring-  oxidation 137 

Amoeba,  the 114 

Amoeboid  motion  of  white  blood  corpuscles 207 

Aneurism,   Hunter's  treatment  of. 4 

Animal  bodies  as  machines 43 

Animals,  fertility  of 94 

Appendix   vermiformis  as  rudiment 80 

Artificial  selection 90 

"  "  effects   of. 92 

"         construction  of  organic  bodies 41 

Assimilation,  the  property  of 52, 132 

Atavism 87,89 

Atmosphere,  maintenance  of  composition  of 43 

Aubrey  John,  remarks  concerning  Harvey 3 

Autogeny 141 

Axis  cylinder,  the 228 

Bathybius,  the 113 

Bee,  generation  of 127 

Birds,  action  of  muscles  in 221 

*'         classifications  of. 92 

Blood  albumen 269 

M         and  its  properties 247 

**        as  source  of  life 272 

"         as  substitute  of  the  body 272 

"         coagulation    of. 2G9 

«         color  of 252 

*«        constitution  of 251,  268 


274  INDEX. 

Blood  corpuscles  colored 265 

"  "  colorless 2G6 

**  "  affected  by  coagulation 270 

"  "  red 250 

"  "  "    constitution  of .., 2G4 

"  "  "  elasticity  of. 203 

"  "  "    number  of. 203 

"  "  "    size  of. 2C0 

"  "  "   use  of. 2G5 

"        dependence  of  muscle  on 217 

"         fibrin  of. 269 

"  "      use  of 270 

"         morphology  of. 258 

"        odor  of. 253 

"         of  man  and  animals 71 

"         oxidation  processes  in 136 

"      .  plasma 2G8 

"         proximate  principles  of. 2G9 

"        quantity  of. 255 

"        reaction  of. 253 

'*        spectroscopy   of 265 

"        taste  of. 254 

**        temperature  of. 254 

"        transfusion  of 248 

"        value  of 247,  272 

"        weight  of 255 

"        vessels,  contractility  of. 197 

Bone,   absorption  by 172 

"        air  in 170 

"         and  its  properties 150 

"        as  a  connective  tissue 164 

"         as  fuel 158 

**        as  symbol  of  the  body 174 

"        canaliculi 155 

"        centres  of  ossification  in 1G7 

"         chemistry  of. 15G,  159 

"        corpuscles 155 

"        constancy  of  composition  of 159 

14         distortion  effected  by  weight 173 

•*         effects  of  use  and  disuse  on 172 

"         excavation    of 109 

"         formation  in  anomalous  places 164 

*'  "  of 105 

M        general  properties  of. 152 


index.  275 

Bone,   harmony  of  development  of. 173 

"        Haversian  canals  of. 153 

"         histology  of. 153 

44         lamellae  of 154 

44         marrow  of. 171 

44         studies  in  living 171 

44        preservation  of. 103 

"        phosphate  of  lime  in 1C2 

44        relation  to  nerve  tissue 150 

44        resistance  and  resilience  of 150 

44         rudiments 78 

Brain  of  man  and  animals 70,  71 

Brambles,  classification  of 92 

Branchial  clefts 75 

Cadaveric  rigidity 212 

Canaliculi  of  bone 155 

Cancellated  structure  of  bone 109 

Carbon  compounds  in  plants 40 

Carbonic  acid  gas,  decomposition  of  in  plants 39 

Carotid  process,  the 233 

Cataclysms  of  Cuvier 58 

Caterpillar,  colors  of 98 

Cats  and  red  clover 101 

Caul,  the 10 

Cell,  chemistry  of. 131 

44      contents  or  protoplasm 113 

44      derivation  and  import  of  the  term 110 

44      discovery  and  history  of  the 108 

44      metabolism  of 133 

44      mode  of  birth  of. 144 

44         44      44    death  of. 145 

44      nucleus  and  nucleolus „ 112 

44      pigment  in  chameleon 118 

44      shape  and  size  of. 109 

44      wall ..: HI 

Centre  of  ossification KJ7 

Cerebro-spinal  and  sympathetic  systems 220 

Cerebrum,  action  of  cells  of 239 

Chameleon,  color  changes  in 117 

Chamisso  on  alternation  of  generation 87 

Channel  of  Mt.  Pilatus 37 

Chemistry  of  blood 2G4,  208 

44  44    bone 15G,  159 

"         44    the  cell 131 


276  index. 

Chemistry  of  muscle  184 

"  "    nerve  tissue 2)15 

"  "     protoplasm ; 123,  1.11 

Child,  resemblance  of  to  parent 80,  00 

Chorda  dorsalis,  discovery  of  cell  structure  of 110 

"  "  ossification   in 1G7 

Cilia  and  ciliary  motion 110 

Ciliary  motion,  conditions  affecting- : 121 

Circulation,  discovery   of..... 2 

"  value  of  knowledge    of 4 

"  work  on.... 2 

Classification  of  tissues 146 

"  ".       "         anatomical 147 

"  "        "         chemical 147 

"  "        "         physiological 148 

"  "    animals  and  plants,  difficulty  of. 01 

Clocks,  the  force  which  runs 27 

Clover,  red  and  cats 101 

Coagulation  of  the  blood » 200 

Coal,  magazines  of 40 

Coccyx  as  rudimentary  organ 78 

"        muscles  of 70 

Color  changes  in  chameleon 117 

"      of  blood 252 

"        "  flowers, use  of 101 

"        "  muscle 177 

"        "   nerve  tissue 226 

Colors,  protective 07 

'*         warning 07 

Combustion,  excretions  as  products  of 41 

"  gases  of 41 

Comparative  anatomy,  evidence  furnished  by 01,  65 

"  embryology 73 

Conservation  of  force 2') 

Contraction  process  as  cause  of  heat  of  the  sun 36 

Conservatoire  des  Arts  et  des  Metiers 29 

Contractility  of  muscle  (see  muscle) 

Convertibility  of  the  forces 26,  29 

Corpuscles,  blood  (see  blood). 
"  bone  (see  bone). 

"  of  Pacini 230 

"  of  Krause 230 

"  tactile 230 

Cranium,  bones  of. C8 


INDEX.  277 

Curare,  action  on  muscle 207 

Curve,  the  muscle 203 

Cuvier,  cataclysms   of 58 

"  on  comparative  anatomy C5 

**  "    footprints G2 

Darwin  Charles  Robert,  discoveries  of 91 

"         Erasmus 70 

"         on  imperfection  of  geological  record G3 

"        views  on  rudiments 83 

Death  of  cells 145 

Decay,  action  of  upon  matter 25 

Denudation  of  earth,  rate  of. 58 

Diemerbroeck's  treatment  of  small-pox 7 

Digestive  system,  rudiments  in 79 

Digitalis,  action   of 12 

Disease,  ontological  conception  of 5 

Diseases  transmitted  by  inheritance 85 

Drinking  water,  lime  salts  in 162 

Du  Bois-Reymond1s  theory  of  muscular  action 210,  211 

Duck,  resistance  of  to  asphyxia 2G6 

Dynamometer,   the 219 

Ear,  comparative  anatomy  of. G5 

"     external  as  rudiment ; 81 

"     lopped  in  rabbits  effect  on  bones 173 

"     rudimentary  muscles  of xm    79 

"     the  point  of  as  rudiment ; 81 

Earth,  age  of 59 

"       effect  of  arrest  of  rotation  of 35 

"      past  history  of 55 

Egg  (see  ovum). 

Egg,  oxidation  processes  in 135 

Elasticity  of  muscle „ 185 

Electricity,  action  of  on  muscle 201   203   201 

"  action  of  upon  nerve  tissue... 23G 

u  and  nerve  force 241 

"  generation  in  muscle 209 

44  light  from 31 

"  motion  from : 31 

Electrotonus  of  nerve  fibre 237 

Elements,  ultimate  composing  organic  matter 129 

Emboli 271 

Embryology    comparative 73 

Endogenous  development  of  cells 144 


278  INDEX. 

Epiphyseal  centre  in  femur 108 

Equivalence  of  the  forces 28 

Ergot,  physiological  action  of. 14 

Evolution,  the  theory  of. 50 

Excretions  as  products  of  combustion 41 

Exercise,  influence  of  on  nerve  tissue 245 

Existence,  the   struggle  for ." 94,  96 

Existing  causes,  operation  of 59 

Experience,  the  fallacy  of 4 

Eye,  rudimentary  structure  in 81 

**     comparative  anatomy  of. 65 

Facial  bones,  air  in 171 

"       neuralgia  nerves  affected  in 12 

Fatigue,  effect  on  muscle 1S5 

"  sensation  of. 191, 102 

Femur,  epiphyseal  centre  in 108 

Fertility  of  plants  and  animals 94 

Fcetus  of  man  and  animals 74,  75 

Fibrin,  blood 209,270 

Filum  terminale  as  rudiment 80 

Fire,  action  of  upon  matter 24 

Fishes,  air  in  bones   of. 170 

Flowers,  use  of  smell  and  colors  of. 101 

Food  and  fuel,  relative  cost  of. 44 

"      as  source  of  force 39 

11      force  value  of 4.1 

"      in  relation  to  work 44 

Foot  of  man  and  animals 76 

Foot  prints  as  evidence 62 

Force,  conservation   of 2i> 

"        machinery  a  means  of  changing 27 

«        muscular 218,  219 

M        nerve,  the 237 

"        no  matter  without 25 

"        perpetuity  of 38 

M        physiological 39 

Forces,  convertibility   of  the 26 

M         equivalence    of 28 

Fossils,  explanations  of 56 

Fuel,  bones  as l,r'8 

"      and  food  relative  cost  of 44 

Galvani  and  galvanism 202 

Gases  of  combustion 41 

Gelatine  as  an  aliment *58 


INDEX.  279 

Generation,  alternation  of. 87 

*'  spontaneous  141 

Genesis  of  protoplasm 140 

GcofFroy  St.  Ililaire  on  rudiments <c2 

Geological  record,  imperfection  of 63 

Germinal  vesicle,  molecules  in 89 

Gesticulation,  action  of  muscle  in 222 

Gladstone's  response 16 

Goethe,  views  on  development  of  life G9 

"  Wilhelm,  work  of OS 

Gravitation,  conversion  of  into  heat 37 

Haeckel  Ernst,  work  of. 74 

Hair  bulbs,  terminations  nerve  fibres  in 231 

Hairs  as  rudiments 80 

Haller  Albert,  sketch  of  life  of 19 

"        works  of,  opinions  concerning 21 

Hand  and  its  homologies 72 

Haversian  canals 153 

Harvey  William,  discovery  of  the  circulation 2 

.      "  "  life  of 17 

Heat  caused  by  gravitation 37 

"      effect  on  muscle 200 

"     generation  of,  in  muscle 208 

"      mechanical  equivalent  of. 29 

"      motion  converted  into 30 

"      of  sun  from  contraction 36 

"      solar,  origin  of 25 

Hemaglobin 264 

Hematin 264 

Heredity  (see  inheritability). 

Histology,  history  of 105 

Homoeopathy  and  the  school  of  Naples 15. 

Homochronous  transmissions 87 

Horses,  phenomena  of  reversion  in 88 

Human  beings,  fecundity  of 95 

Humboldt's  estimate  of  forms  of  life 64 

Humerus,  supra-condyloid  process  of. 78 

Hunger  as  cause  of  preservation  of  race 103 

Hunter  John,  treatment  of  aneurism 4 

Inheritability,  examples  of 85 

"  explanation  of 89 

"  homochronous 87 

*4  in  lower  animals 86 


280  IXDEX. 

Inheritability,  influence  on  the  mind 239 

'*  laws  of. 84 

Infusoria,  fecundity  of 95 

Insects,  action  of  muscles  in 221 

winged  and  wingless  ..7. 96 

Intermaxillary  process 09 

Janssens  Zacharias  and  the  microscope  107 

Jellies,  nutritive  principles  in 15S 

Kant,  nebular  hypothesis  of 34 

King's  evil,  royal  touch  as  cure  of 9 

Kolliker  on  the  cell.. 112 

Lamarck  Jean,  works  of 6G,  90 

Lamellae  of  bone 154 

Lanugo  as  rudimentary  structure 81 

Laplace,  nebular  hypothesis  of 34 

Laryngismus  stridulus  a  reflex  affection  12 

Lecithin  and  cerebrin 235 

Leeuwenhoek,  discoveries  of. 107 

Leg  of  man  and  animals 76 

Levers,  muscles  as 217  " 

Life,  definitions  of 48 

"      period  of  development  of 54 

Light  from  electricity 31 

Lime  phosphate  in  bone 102 

Links  missing,  cause  of 62 

Liquor  sanguinis 26S 

Locomotive,  derivation  of  force  of 28 

Machinery,  a  means  of  changing  force 27 

Machines,  animal  bodies  as 43 

Madder,  absorption  of  by  bone 172 

Malpighi,  discoveries  of 107 

Man,   ancient 61 

"        position  of  in  animal  scale 72 

Marrow  of  bone , 171 

Matter  indestructibility  of 24,  38 

no,  without  force 25 

Maturitv  at  birth,  determination  of 168 

Mechanisms  and  organisms 51 

Meckel,  ganglion  of. 12 

Metabolism  of  the  cell 133 

Meteors,  fall  of  upon  the  earth 30 

Metrorrhagia,  ancient  treatment  of. 13 

Microscope,  history   of 1Q7 


INDEX.  281 

Mid-jaw  bone 69 

Miraculous  and  non-miraculous  theories  of  life 54 

Molecular  movements 123 

Molecules,  size  and  number  of  in  ovum 89 

Moliore's  satires  upon  medicine 8 

Monkeys,  sense  of  taste  in 71 

Motion  as  essence  of  reproduction 12G 

"        ciliary 119 

"        conversion  of  into  heat 30 

"        from  electricity,  examples  of 31 

"        molecular 123 

*'        muscular 176 

"        of  white  blood  corpuscles 2G7 

"        property  of  in  protoplasm HG 

Mueller  Johannes  and  the  chorda  dorsalis 110 

Muscle,  absolute  power  of. 218 

"         action  of  curare  on 207 

"  "       "  nerve  force  on 203,225 

"  '*       "  sulphocyanide  of  potash  on 206 

"  «      persistence  of  after  death 212 

*'  and  nerve  plate . 232 

"  and  its  properties 175, 195 

"         as  levers 217 

"  chemistry  of 184 

"  color  of 177 

"  connection  with  tendons 197 

"         contractility 195 

*«  "  agents  which  induce  199 

**  "  change  of  form  in 198 

"  "  degree  of 198 

"  "  direct  and  indirect  excitation  of 200 

"  '      «  effect  of 197 

«  "  independence  of. 20G,  208 

«  ««  electric  excitation  of 201,203,204 

"  "  thermal  excitation  of 200 

"  "  rate  of  conduction  of 20G 

«  «  sound  of. 205 

*'  curve 203 

"  dependence  of  upon  blood 217 

"  difference  in  different  animals 220 

"  disks  179 

*'  elasticity  of. 1S5 

"  etymology  of 175 

«4         fibre  and  fibrilla 179 

24 


282  INDEX. 

Muscle,  force  and  nerve  force 238 

"  form  and  shape  of 182 

"  fuel  of. 23 

"  general  power  of 219 

"  "        properties  of. 180 

*'  generation  of  electricity  in 209 

"  "  "   heat  in 208 

"  in  birds  action  of. . 221 

"  in  insects  "         **   221 

"  involuntary 182 

"  "  contractility  of 196 

u  "  disposition  of ,...„■ 183 

u  motion  effected  by 176 

"  names  of 181 

'*         oxidation  of 216 

"  "  processes  in 135 

"  oxygen  supply  to 216 

"  post-mortem  changes  in ., 214 

"  products  of  action  of a  215 

"  protoplasm 180 

"  reaction  of. 184 

"  rigor  mortis  of 212 

"  rudiments , 79 

"  sarcolemma  of. 178 

"  sense,  exercise  of , 193 

"  "        and  sense  of  touch 190 

"  sensibility  of 190 

"  sexual  differences  in ..„ 220 

"  specific  properties  of. 185 

"  striped  and  smooth 176 

"  termination  of  nerve  fibres  in  231 

"  tonicity  of 187,  188, 189 

"  transfusion  of  blood   nto 47 

M  velocity  and  delicacy  of  action  of 221 

"  voluntary,  anatomy  of. 178 

"  wave,  the 205 

Muscular  force,  source  of  in  food 39 

Naples,  school  of  and  homoeopathy 15 

Napoleon,  advice  to  Antonamarchi 8 

Natural  selection 90 

"  "         complications  in 100 

"  "         illustrations  of. 96 

Nebular  hypothesis 34 

Nerve,  ancient  significance  of. 244 


INDEX.  283 

Nerve  and  its  properties 223 

as  tendon 244 

cells 227 

"      and    fibres 225 

fibres 227 

"       axis  cylinder  of 228 

"       course   of 232 

"       gray .229 

"       identity  of. 234 

"       indifference  of  direction  of  nerve  force  in 235 

"       medulla  of. 228 

"       motor,  terminations  of. 231 

"       sensitive        "  " 230 

"       sheath  of . 227 

force,  action  of  in  cold  blooded  animals 243 

"  "         "  upon  muscle 204,225 

44  and  electricity 241 

44  genesis  of. 225 

"  independence   of. 224 

"  nature  of. 237 

"  rate  of  conduction  of 240,  242 

tissue  action  of  electricity  upon 236 

44       arrangement  of. 22G 

44       chemical  processes  in 236 

44       chemistry   of 235 

44       color   of. '.'. 226 

44       divisions   of. 226 

44       effects  of  age  on 246 

44  44        44    use  and  disuse „.  245 

44  oxidation  in 138 

44  prime  function  of. 223 

44  reception  and  perception  of  impressions  by ". 242 

44  relation  of  bone  to 150 

44  subordination  of. 224 

Nerves,  properties  of. „ 229 

Nictitating  membrane  of  the  human  eye 81 

Nucleus  and  nucleolus  of  the  cell 112 

44         44  44  44     44      44   chemistry  of 132 

Number  of  species 94 

Nutrition  and  reproduction 143 

44  the  circle  of. 42 

Occupation,  effect  of  on  bones 173 

Ophthalmology,   progress  of 13 

Opinions  of  medicine  by  noted  men „     7 


284  raDEx. 

Organic  and  inorganic  matter,  difference  between 51 

"        bodies,  artificially  compounded 41 

"         matter,  chemistry  of 128 

Organisms   and  mechanisms 51 

Ossification,  the  centre  of. 1G7 

Osteology,  difficulties  attending  the  study  of. 157 

Osteo-malacia  and  rachitis 161 

Ova,  number  of  in  human  being 96 

Ovum  as  typical  cell 109 

"      molecular  changes  in 124 

"      multiplication  of  cells  of 89 

"      oxidation  processes  in 134 

M      size  and  number  of  molecules  in  89 

Oxidation,  processes  of 133 

Oxygen,  absorption  of  in  blood 265 

"         consumption  of  in  the  body  42 

"         quantity  of  in  the  body 138 

"        supply  to  muscle 216 

Ozone  in  blood  corpuscles 137 

Palaeontology,  the  science  of 56 

Palm  tree,  fructification  of 100 

Paracelsus  Theophrastus 5 

Paraguay,  absence  of  wild  cattle  in : 100 

Parent,  resemblance  of  child  to 89,  90 

Parthenogenesis 126 

Periosteum,  the , 166 

Perpetuity  of  matter  and  force 38 

Phosphate  of  lime  in  bone 162 

Phosphorus  in  nerve  tissue .- 236 

Phthisis,  treatment  by  venesection 6 

Physician,  requisitions  of  ancient 16 

"  the  modern 15 

Physics  of  reproduction 88 

Physiological  force 39,  46 

Physiologists,  characteristics  of. 21 

Physiology,  contributions  of  to  practice 11 

"  definitions  and  synonims  of 47,  50 

M  influence  of  on  practice 1 

'*  study  of  as  a  refuge 22 

Pigeon  breeders,  experiments  of 93 

Pigeons,  varieties  of  under  artificial  selection 93 

Pigs,  fecundity  of. 102 

Pigment  cells  in  chameleon 118 

Pilatus  Mt.,  channel  of 37 


INDEX.  2S5 

Planetary  system,  commencement  of 34 

Plants,  carbon  compounds  in 40 

"         fertility  of 94 

Plasma,  the  blood 268 

Plica  semilunaris 81 

Point  of  the  ear  as  rudiment 81 

Pregnancy,  post-mortem  recognition  of  previous 25 

Prescriptions  ancient,  specimens  of 5 

Preservation  of  individual  and  race 102 

Primrose  Dr.  Jacob 1 

Protective  colors 97 

Protoplasm  and  its  properties 105, 113,  115,  128 

"  chemistry  of. 131 

'*  examples  of. 115 

"  genesis  of 140 

"  muscle,  fluidity  of 180 

Proximate  principles  129 

"  "  in  the  blood 269 

Pus  corpuscles 267 

Rabbits,  displacement  of  bones  of. 173 

"         varieties  of  under  artificial  selection 94 

Rachitis  and  osteo-malacia 161 

Rattle  snake,  rattle  of 99 

Reflex  action 237 

"      affections  13 

Renal  force,  the 220 

Reproduction  and  nutrition 143 

"  instinct  of  in  preservation  of  race 103 

"  process  of  as  distinction  of  organic  matter 52 

'•  the  physics  of 88,  124 

Resemblance  between  man  and  animals 70 

"  of  child  to  parent,  reason  of 89,  90 

Resiliency  of  bone 159 

Resistance  of  bone  159 

Reversion,  phenomena  of 87,  89 

Rib,  manufacture  of  female  from 174 

Rigor  mortis 212 

Royal  touch,  the 9 

Rudimentary  organs 77 

"  "        bone 78 

"  "         digestive  system 79 

"  u        explanations  of 82,  83 

"  "        from  eye  and  ear 81 

"  "        hair  as 81 


286  ixdex. 

Rudimentary  organs,  muscle t    79 

"  "         spinal  cord 80 

Salpae,  alternation  of  generation  in 87 

Sarcolemma  of  muscle 178 

Schwann  Carl  Theodor  and  the  cell 108 

"  white  substance  of ....228 

Science  versus  practice -m  3 

Sea-buoys,  alternation  of  generation  in 88 

Segmentation  process  of  in  ovum 125 

Selection,  artificial 00 

"  "       effects  of. 92 

"  natural GO 

"  "       complications  in 100 

"  "      illustrations  of. 96 

"  "       sexual  98 

Semilunar  fold  in  the  eye  as  rudiment 81 

Sensibility  of  muscle 190 

"  "         "      and  sense  of  touch , 190 

Sense  muscular,  exercise  of. 193 

Sensitive  nerves,  terminations  in'  muscle 191 

Sexes,  difference  of  muscle  in 220 

Sexual   selection 98 

Sharpey's  bone  lamellae 154 

Sheath  of  nerve  tubes 227 

Ships  and  force  of  the  wind ; 28 

Signatures,  doctrine  of  in  the  treatment  of  small-pox 6 

Skeleton,  the 151 

Smell  of  flowers,  use  of 101 

Small-pox,  doctrine  of  signatures  in 6 

Sound  of  muscle  contraction 205 

Solar  origin  of  heat 25 

Species,   mutabdity  of. 92 

Spectroscopy  of  the  blood 265 

Spermatozoids  as  cdiated  cells 122 

"  action  of  towards  ovum 125 

"  discovery  of 107 

Spinal  cord,  termination  of  as  rudiment 80 

"  u       relation  of  bone  to 150 

Spontaneous  generation 141 

Starch,  formation  of 26 

Steam  engine,  the  force  of 28 

Stephenson  George,  conception  of  heat 25 

Sterne,  description  of  receipt  by 5 

"        opinion  of  medicine  by 8 


INDEX.  287 

Struggle  for  existence 94,  90 

Succession,  order  of  vertebrate , 66 

Sugar,  formation  of 26 

Sun  as  the  source  of  force 25,  32 

"    dimensions  of 32 

*'    heat  of  caused  by  processes  of  contraction 36 

"    origin  of  forces  of 33 

Sympathetic  and  cerebro-spinal  systems 226 

Tad-poles,  cells  of  chorda  dorsalis  of. , 110,  111 

Temperature  of  the  blood 254 

Tendons  and  nerves 244 

"  connection  With  muscle  fibre 197 

Theories  of  life .....* 54,  55 

Tic  doloureux 12 

Tissues,  classification  of  the , 146 

Tonicity  of  involuntary  muscle 189 

"        "  muscle 187 

"         "         "      a  reilex  phenomena  188 

Tooth,  wisdom  as  rudiment 79 

Touch,  sense  and  sensibility  of  muscle 190 

"        the  royal : 9 

Transfusion  of  blood 248 

"  "      "      into  muscles 217 

Uterus,  resistance  to  putrefactive  change 214 

Universe,  infinitude  of. 38 

Valves  of  veins,  Harvey's  study  of 18 

Velocity  of  muscular  contraction 221 

Vermiform  appendix  as  rudiment 80 

Vertebrata,  structures  peculiar  to 268 

Vertebrate  animals,  bone  tissue  in 150 

Vesicle  germinal,  molecules  in 89 

Volitional  action  238 

Virchow's  opinion  of  ophthalmology 13 

Virgin  generation 126 

Vital  force,  the 210 

Vocal  cords,  muscular  movements  of. 222 

Vulpian  on  brain  of  man  and  animals 70 

Wall,  the  cell Ill 

Warning  colors 97 

Water  drinking,  lime  salts  in 162 

"       -wheels,  the  force  of 27 

Wave,  the  muscle 205 

Whale,  perception  of  impressions  in 243 


288  index. 

Wind,  fertilisation  by  „ 102 

Windmills,  the  force  of '. 27 

Wisdom  tooth  as  rudiment 79 

Woorara,  action  on  muscle 206 

Work,  relation  of  food  to , 44 


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presented  in  such  a  natural  and  interesting  manner  that  the  reader,  before 
he  is  aware,  has  become  interested,  and  is  deeply  absorbed  in  the  perusal 
of  the  work.  Even  with  one  who  is  quite  conversant  with  physiology, 
and,  therefore,  meets  with  nothing  that  he  is  not  already  familiar  with 
there  is  an  attractiveness  in  the  lectures  which  begets  "an  interest  and 
leads  him  to  become  engrossed  in  reading.  *  *  We  advise  our  readers, 
if  they  wish  something  readable,  something  they  can  give  their  whole 
attention  to  without  any  effort,  something  that  will  instruct  at  the  same 
time  it  affords  relaxation,  like  J.  S.  C.  Abbott's  histories,  to  purchase  this 
little  work  on  physiology  by  Dr.  Whittaker." — Cincinnati  Medical  News. 

"Our  author  makes  no  claim  to  originality  or  to  full  exposition  of  the 
principles  of  Physiology,  but  he  has  given  a  readable  little  volume, 
written  in  novel  style,  well  arranged  and  filled  with  much  that  will  be 
new  and  curious  to  the  first  course  student,  for  whom  the  work  is  mainlv 
designed.         *  *         The  publishers  deserve  credit  for  the  admira- 

ble appearance  of  the  work." — Philadelphia  Medical  Bulletin. 


[»] 

"It  is,  moreover,  one  of  the  best,  if  not  the  best,  books  we  know  of  to 

filace  in  the  hands  of  the  young'  man  just  taking  up  the  study  of  medicine, 
t  will,  we  are  confident,  interest  him  in  the  study  of  physiology,  and 
qualify  him  for  more  thorough  reading." — Michigan  Medical  News. 

"We  heartily  commend  this  work  to  all  lovers  of  the  charming  study 
of  physiology.'1 — Denial  News'. 

"This  book  of  nearly  three  hundred  pages  is  well  bound,  printed  and 
illustrated,  and  is  besides,  well  written.  The  style  is  easy  and  flowing; 
in  a  word,  it  is  very  interesting,  and  we  can  commend  the  book  to  lovers 
of  Physiology." — St.  Louis  Medical  Brief. 

"This  volume  of  nearly  three  hundred  pages  is  made  up,  as  its  title 
implies,  of  the  lectures  which  its  author  has  delivered  preliminary  to  his 
courses  upon  Physiology  in  the  Ohio  Medical  College.  *  *  These_ 
matters  are  treated  in  a  very  scholarly  and  graphic  manner.  Indeed 
Prof.  Whittaker  is  one  of  the  most  accomplished  of  American  medical 
writers,  and  seldom  fails  to  invest  his  themes  with  great  interest.  There 
is  much  in  his  present  work  to  instruct  and  to  be  enjoyed." — Louisville 
Medical  News. 

"Dr.  Whittaker  has  given  the  profession  a  little  volume,  which  he 
designs  for  first  course  students.  The  reading  is  delightful,  the  text  and 
paper  excellent,  and  the  whole  subject  fully  up  to  t lie  times.  While  it 
may  be  specially  intended  for  students,  no  practitioner  can  read  it  with- 
out being  benefited.  There  is  a  great  deal  of  matter  entirely  new  to  us, 
and  the  doctor,  it  seems,  is  not  only  a  good  physiologist,  but  a  chaste 
scholar,  as  is  evinced  by  his  thorough  acquaintance  with  classical  medi- 
cal literature,  and  the  pleasant  style  of  his  writing.  No  student  of 
medicine  should  be  without  this  sine  qua  non  in  physiology." — Southern 
(Richmond)  Clime. 

"The  work  is  one  which,  while  it  will  be  most  thoroughly  enjoyed  by 
those  who  heard  the  gii'ted  author  originally,  will  be  fully  appreciated  by 
students  everywhere,  and  by  practitioners  as  well.  We  have  read  the 
work  carefully,  and,  though  there  are  a  few  minor  points  for  criticism, 
the  book  is  thoroughly  enjoyable  from  beginning  to  end." — Ohio  Medical 
Recorder. 

"We  hail  this  little  book  with^leasure;  it  is,  as  the  author  states  in  his 
preface,  and  as  the  title  shows,  a  course  of  preliminary  lectures,  such  as 
are  intended  for  the  student  before  entering  the  study  of  physiology 
proper  and  the  remaining  purely  medical  subjects.  It  is  time  that  pre- 
liminary work  of  this  sort  should  be  done  by  the  student,  and  the  only 
excuse  that  could  be  given,  heretofore,  was,  that  we  possessed  no  text 
books  from   which  this  knowledge  could  be  obtained.  *  * 

This  little  book  is  so  written  that  it  fills  one  of  these  vacuoles.  In 
taking  up  the  subjects  as  1  as  been  done,  the  author  has  furnished  a  work 
not  only  useful  to  the  medical  man  but  also  instructive  to  the  layman.     *     * 

"From  this  brief  outline  can  be  seen  what  is  aimed  at  by  the  author. 
We  can  not  claim  anything  original  for  the  little  work,  except  for  the 
manner  in  which  the  material  has  been  handled  and  brought  together. 
For  this  we  can  say  that  it  has  been  done  in  a  masterly  way.  Prof. 
Whittaker  has  capital  ideas  ret,-:'. rding  the  getting  up  of  a  book;  thus  we 
see  an  outline  of  the  book  published  under  the  title  of  contents,  this  out- 
line carried  out  throughout  the  whole  book,  the  captions  serving,  as  it 
were,  for  paragraphs,  bringing  the  matter  treated  of  directly  and  posi- 
tively to  the  attention  of  the  reader,  and,  in  addition  aiding  him  in  keep- 
ing up  a  logical  connection  of  thought.  The  book  is  illustrated  by  three 
pages  of  very  good  engravings,  the  typographical  work  has  been  well 
done,  and  the  modest,  tasteful  appearance  of  the  work  will  do  no  little  to 
recommend  it.  Let  us  have  more  of  this  kind  of  work,  and  the  American 
student  will  soon  be  able  to  cope  with  his  foreign  brethren  in  regard  to 
preliminary  knowledge." — Cincinnati  Lancet  and  Clinic. 

"Professor  Whittaker  is  well  known  as  a  thinker  and  a  writer,  and  he 
gives  us  here  a  very  interesting  and  useful  book,  so  well  spiced  with  the 
assumed  facts  and  doubtful  conclusions  of  the  extreme  physiological 
school  of  the  day,  as  to  impart  to  it  the  air  of  a  pleasant  romance.  One 
of  the  heads  we  notice  is:  'The  Fallacy  of  Experience.'  The  doctrine  of 
evolution  and  the  eternhy  of  matter  arc  taught  as  settled  questions.  We 
doubt  the  propriety  of  traveling  beyond  the  strict  limits  of  physiology  in 
a  medical  school,  to  inculcate  sentiments  which  may  be  hostile  to  the 
religious  opinions  of  the  youtii  who  are  committed  to  the  charge  of  the 
professors. — Pacific  Medical  and  Surgical  Journal. 

\ 


[3] 


"The  lectures  are  interspersed  with  anecdotes,  apt  quotations  from  all 
sources,  scientific  and  literary;  a  little  biography,  notably  of  Harvey  and 
Haller,  the  founders  of  modern  physiology;  and  historical  sketches  of 
some  of  the  fundamental  principles  of  natural  science.  *  * 

'-While  only  the  outlines  of  the  several  subjects  are  given,  the  book  is 
most  interesting  and  instructive,  not  only  to  hrst-course  students,  but  to 
many  whose  'first  course'  was  taken  years  ago.  It  presents  in  concise  and 
agreeable  form  the  general  principles  of  physiology  and  the  doctrines  of 
evolution  and  development,  and  of  conservation  and  correlation  of 
force.         *         * 

"The  work  displays  extensive  reading  and  the  possession  of  a  wonder- 
ful memory  on  the  part  of  the  brilliant  lecturer.  It  is  not  surprising  that 
the  class  urgently  requested  putting  the  lectures  into  book  form." — 
Toledo  Medical  and  Surgical  journal. 

"It  occupies  a  position  that  has  heretofore  been  vacant,  at  least  so  far 
as  any  single  work  is  concerned.  It  is  a  work  valuable  to  every  specialist 
as  well  as  to  the  general  practitioner.' ' — The  Dental  Register. 

"Any  student  who  may  have  the  fortune  to  have  as  good  a  foundation 
in  physiology  as  Dr.  Whittaker's  book  can  give  him,  may  feel  sure  that 
he  i.i  in  the  right  way  to  a  comprehensive  grasp  of  the  complete  subject. 
Students  are  very  prone  to  neglect  the  history  upon  which  our  modern 
science  of  physiology  is  built,  and  in  doing  this  they  neglect  the  most 
charming  chapter  in  the  development  of  human  learning." — North 
Carolina  Medical  Journal. 

"Wo  regret  very  much  that  our  space  will  not  allow  us  to  say  what  we 
would  like  to  say  in  favor  of  this  work. 

"Its  style  is  classic.  It  is  up  to  the  times.  It  is  scientific  in  its  method. 
It  is  comprehensive  and  instructive,  especially  to  those  wishing  to  become 
familiar  with  Darwinism.  We  wish  we  could  reprint  the  lecture  on  'The 
Influence  of  Physiology  upon  the  Practice  of  Medicine,'  for  we  believe 
it  would  be  especially  useful  to  the  young  men  of  the  profession." — The 
Herald  of  Health. 

"This  is  a  series  of  preliminary  lectures  upon  the  subject  of  physiology, 
the  object  of  which  is  to  inculcate  the  lessons  of  the  ground  work  of  that 
great  subject  in  the  minds  of  students  and  to  familiarize  him  with  great 
truths  in  small  compass,  which  can  only  be  obtained  otherwise  after 
laborious  search  through  the  extensive  literature  upon  the  subject.  It  is 
well  written  and  does  the  distinguished  author  credit." — Nashville 
Journal  of  Medicine  and  Surgery. 

"Dr.  Whittaker  has  presented  his  students  with  a  most  readable  volume, 
one  that  many  old  students,  i.  e.,  practitioners,  might  read  with  great 
advantage.  The  theory  of  evolution  is  taught  with  much  clearness  and 
force,  and  even  those  who  disbelieve  the  doctrines  of  Darwin  and  Huxley 
will  find  it  very  interesting  and  instructive.  We  do  not  know  of  a  better 
presentation  of  the  subjects  treated  of  in  concise  form  than  this  handy 
volume.  We  heartily  commend  the  book  to  our  younger  readers." — St. 
Louis  Clinical  Record. 

"All  well  wishers  of  doctors  and  their  clients  owe  Dr.  Whittaker 
thanks  for  the  elevated  ideas  of  physiology  and  its  mission  inculcated  in 
these  lectures;  for  although  he  presents  them  as  only  the  introduction  to 
the  great  science,  still  we  can  feel  assured  that  when  an  architect 
fashions  and  finishes  a  portal  in  beauty  and  appropriateness,  the  temple 
to  which  it  leads  has  been  conceived  and  constructed  in  harmonious  aad 
symmetrical  grandeur." — American  Practitioner. 

"These  are  very  admirable  lectures,  and  deserve  to  become  popular. 
The  author  has  covered  ground  which  is  of  vital  importance  in  physio- 
logical teaching,  but  which  few  lecturers  have  time  to  go  over.  We  refer 
especially  to  the  subjects  of  conservation  of  force,  evolution,  and  the 
properties  of  protoplasm.  The  author's  treatment  of  these  questions  is 
clear  and  thorough,  and  though  somewhat  elementary,  probably  few  will 
find  it  too  much  so.  Evolution  is  taught  as  an  accepted  fact.  To  this 
there  can  be  no  objection  as  long  as  the  evolutionist  does  not  claim  to 
know  and  teach  all  the  forces  and  laws  which  govern  development,  and 
does  not,  further,  claim  that  the  process  is  one  of  gradual  and  uniform 
progression.  That  the  present  orderly  universe  has  been  slowly  evolved 
from  a  low  and  simple  to  a  higher  and  complex  form,  cannot  be  doubted. 
*  *  It  is  but  just  to  say  that  in  this  book  there  is  no  dogmatism  any- 
where, but  disputed  questions  are  stated  fairly  and  left  to  the  judgment 
of  his  readers." — N.  T.  Medical  Record. 


L4J 

"We  could  hope  that  every  doctor  in  the  land,  anct  every  intelligent 
person,  would  read  these  pages,  because  we  are  perfectly  satisfied  "that 
the  change  of  thought  thus  induced  would  redound  to  the  advancement 
of  general  medicine." — The  Detroit  Lancet. 

"It  is  written  in  a  very  interesting  and  attractive  style.'1 — Canada 
Lancet. 

"This  little  book  is  very  different  from  what  we  ordinarily  expect  to 
find  in  an  elementary  treatise.  Instead  of  being  a  hasty  and  incomplete 
summary  of  the  more  salient  points  of  physiology,  a  style  of  work  which 
is  only  suitable  for  those  who  desire  the  most  superficial  information, 
Dr.  Whittaker's  lectures  are  only  elementary  in  that  they  treat  of  the 
'foundation  facts  and  principles  on  which  the  stately  edifice  of  physiology 
is  built,'  while  they  are  in  all  respects  in  accord  with  the  latest  researches. 
They  therefore  serve  as  an  excellent  introduction  to  more  extended  study, 
and  are  admirably  suited  to  the  wants  of  a  first  course  medical  student. 
The  book  contains  twelve  lectures  on  the  influence  of  physiology  on 
practice,  on  the  conservation  of  force,  on  the  origin  of  life,  and  the  evolu- 
tion of  its  forms,  and  on  protoplasm,  bone,  muscle,  nerve,  and  blood;  the 
chapters  on  bone,  muscle,  and  nerve  being  particularly  good.  The  paper, 
binding,  and  type  are  excellent." — American  Journal  of  the  Medical 
Sciences. 

"A  small  book  in  octavo  form,  two  hundred  and  eighty-two  pages, 
containing  lectures  'on  the  foundation  facts  and  principles  upon  which 
physiology  is  built.'  The  students  of  the  Medical  College  of  Ohio  can  be 
content  if  all  their  teachers  give  proof  of  the  same  deep  and  manifold 
study  as  these  lectures,  delivered  during  the  preliminary  course,  are 
evidence  of.  Hypocrisy  and  superstition  would  soon  disappear,  and  the 
medical  profession  in  our  great  country  would  be  in  eveuy  respect  the 
advance-guard  of  civilization,  if  it  were  possible  to  promulgate  the  study 
of  physiology  and  to  omit  nothing  it  teaches.  'The  exhibition  of  life  is 
no  more  due  to  an  innate  principle,  a  separate  essence,  a  quid  intus,  than 
is  the  registrv  of  time  in  a  clock,'  are  words  that  give  us  an  idea  on  what 
scientific  basis  the  author  wishes  the  modern  physician  to  stand.  'It  is 
no  answer  whatever  to  say  that  life  is  creation.  Such  an  assertion  may 
satisfy  the  wants  of  the'  emotions,  but  it  will  in  no  way  appease  the 
demands  of  the  intellect  trained,  by  cultivation  in  physical  science,  to 
entirely  ignore  unnatural  explanations  for  natural  events.'  We  know  a 
lecturer  on  physiology  in  a  large  medical  school  who  would  tremble  to 
utter  such  words,  less  yet  put  them  in  print.  The  author's  description  of 
the  influence  of  physiology  on  practice  and  practitioners;  his  almost 
poetical  rendering  ot  the  conservation  and  correlation  of  force;  the  origin 
and  evolution  of  life  and  its  forms,  wherein  he  follows  Darwin;  and  his 
masterly  lectures  on  protoplasm  and  its  properties,  and  on  bone,  muscle, 
nerves,  and  blood,  form  together  a  series  of  instructions  which  may  not 
be  only  of  value  to  the  student  of  medicine,  to  give  him  a  deeper  inside 
view  of  the  workshop  of  nature,  but  which  should  be  read  by  every  indi- 
vidual claiming  classical  modern  education.  There  can  be  no  doubt  that, 
if  the  author  somewhat  differently  arranged  his  book,  to  make  it  accessi- 
ble to  a  larger  circle  of  intelligent  laymen,  this  volume,  as  well  as  its 
author,  would  soon  be  as  favorably  known,  wherever  the  English  tongue 
is  spoken,  as,  for  instance,  the  Works  of  Bock,  Buchner,  anciMolcschott 
are  in  Germany.  We  have  never  before  seen,  in  the  English  language, 
a  book  on  a  subject  connected  with  physiology,  where  so  much  is  con- 
densed into  such  a  small  space,  and  where  with  a  scholarly  English,  the 
rare  facultas  docendi  is  so  effectively  made  use  of.  'Du  sublime  au 
ridicule  il  n'y  a  qu'un  pas'  is  so  frequently  lost  sight  of  in  these  condensed 
works  on  momentous  questions,  that  they  only  should  be  written  by  a 
master-mind  who  thoroughly  controls  his  subject. 

"The  author  cites,  with  "the  same  facility,  Jansen,  Kant,  Koerner, 
Moliere,  Shakspeare,  and  Schiller,  with  which  he  quotes  Haller,  Harvey, 
Haeckel,  Kolliker,  Tyndal,  Schwann,  Virchow,  Carl  Yogt,  and  Goethe, 
the  latter  in  his  double  capacity  as  poet  and  naturalist.  That  he  mentions, 
besides  these  names,  many  Others  well  known  in  the  history  of  biology, 
Hie  reader  can  imagine  from  the  nature  of  the  subject.  The  work  is 
made  more  interesting  yet,  by  the  author  giving,  of  each  different  subject 
he  speaks  of,  a  history  of  its  evolution  ;  i.  e.,  he  follows  up  the  gradual 
development  of  each  theory  from  its  beginning  to  its  present  condition. 
The  latest  achievements  of  comparative  embryology  are  noted  and  made 
more  apparent  by  well-executed  drawings.  We  heartily  recommend  our 
readers  to  add  this  small  but  valuable  book  to  their  library,  and  are  only 
sorry  that  want  of  spaee  forbids  us  to  give  a  larger  abstract  from  it." — 
Philadelphia  Medical  Times. 


